UNITED STATES DEPARTMENT OF THE INTERIOR BUREAU OF … · The Proposed Action: LLOG Exploration Offshore, L.L.C. (LLOG) proposes to conduct a zero-offset, offset, or walkaway vertical

EXPLORATION PLAN FOR ANCILLARY ACTIVITY SEA NO. R-7018

UNITED STATES DEPARTMENT OF THE INTERIOR BUREAU OF OCEAN ENERGY MANAGEMENT

NEW OLREANS OFFICE NEW ORLEANS, LOUISIANA

SITE-SPECIFIC ENVIRONMENTAL ASSESSMENT

OF

EXPLORATION PLAN

NO. R-7018

FOR

LLOG EXPLORATION OFFSHORE, L.L.C.

September 21, 2020

RELATED ENVIRONMENTAL DOCUMENTS

Gulf of Mexico OCS Proposed Geological and Geophysical Activities

Western, Central, and Eastern Planning Areas Final Programmatic Environmental Impact Statement

(OCS EIS/EA BOEM 2017-051)

Gulf of Mexico OCS Oil and Gas Lease Sales: 2017-2022 Gulf of Mexico Lease Sales 249, 250, 251, 252, 253, 254, 256, 257, 259, and 261

Final Environmental Impact Statement (OCS EIS/EA BOEM 2017-009)

Gulf of Mexico OCS Lease Sale

Final Supplemental Environmental Impact Statement 2018 (OCS EIS/EA BOEM 2017-074)

Biological Opinion Oil and Gas Leasing, Exploration, Development, Production, Decommissioning,

and All Related Activities in the Gulf of Mexico Outer Continental Shelf (FWS April 20, 2018)

Biological Opinion of the Federally Regulated Oil and Gas Program Activities in the Gulf of Mexico

(NMFS March 13, 2020)

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FINDING OF NO SIGNIFICANT IMPACT (FONSI) The Bureau of Ocean Energy and Management (BOEM) has prepared a Site-Specific Environmental Assessment (SEA) (No. R-7018) complying with the National Environmental Policy Act (NEPA). NEPA regulations under the Council on Environmental Quality (CEQ) (40 CFR § 1501.3 and § 1508.9), the United States Department of the Interior NEPA implementing regulations (43 CFR § 46), and BOEM policy require an evaluation of proposed major federal actions, which under BOEM jurisdiction includes approving a plan for oil and gas exploration or development activity on the Outer Continental Shelf (OCS).

NEPA regulation 40 CFR §1508.27(b) requires significance to be evaluated in terms of context and intensity. The context and intensity of impacts caused by similar actions to that proposed were examined at a basin-wide scale in the Gulf of Mexico (GOM) in the:

Gulf of Mexico OCS Proposed Geological and Geophysical Activities Western, Central, and Eastern Planning Areas Final Programmatic Environmental Impact Statement (GOM G&G PEIS) (OCS EIS/EA BOEM 2017-051),

Gulf of Mexico OCS Oil and Gas Lease Sales: 2017-2022 Gulf of Mexico Lease Sales 249, 250, 251, 252, 253, 254, 256, 257, 259, and 261 Final Environmental Impact Statement (Multisale EIS) (OCS EIS/EA BOEM 2017-009),

Gulf of Mexico Lease Sale Final Supplemental Environmental Impact Statement 2018 (2018 SEIS) (OCS EIS/EA BOEM 2017-074),

Biological Opinion Oil and Gas Leasing, Exploration, Development, Production, Decommissioning, and All Related Activities in the Gulf of Mexico Outer Continental Shelf (FWS 2018 BO) (Issued by United States Fish and Wildlife Service [FWS] April 20, 2018), and

Biological Opinion on the Federally Regulated Oil and Gas Program Activities in the Gulf of Mexico (2020 BO) (Issued by National Marine Fisheries Service [NMFS] March 13, 2020).

This SEA tiers from these evaluations and considers the impacts of the proposed action.

The Proposed Action: LLOG Exploration Offshore, L.L.C. (LLOG) proposes to conduct a zero-offset, offset, or walkaway vertical seismic profile (VSP), salt proximity survey, and/or checkshot survey with an airgun array that will either be deployed form the deck of the Botruc 41 offshore supply vessel, or mounted from the Seadrill West Neptune rig crane. The receivers for the survey will be deployed in the Well 001 ST00PB00 wellbore. No streamers or source vessels will be used during the survey. The proposed activity is located south of Louisiana in the Central Planning Area of the GOM. The well is located in Ewing Bank Block 921; lease OCS G 36704 and 35295, and the survey area also includes Ewing Bank Block 877, Lease Number G-35295. The area of the proposed action is approximately 67 miles (108 kilometers) from the nearest shoreline. The water depth of the entire survey area in Ewing Bank ranges from 925 – 1,860 feet (ft) (282 - 567 meters (m)). The operation will be using support vessels whose operations are comparable to that described in the GOM G&G PEIS for similar activities. Site-specific analysis was completed using LLOG’s description of the proposed operations; however, specific technical information regarding the G&G activities described in the plan is proprietary and therefore not included in this document. The proposed survey is expected to take approximately 2 days to complete and will begin between October and December 2020.

Factors Considered in this Determination: The context and intensity of the proposed action are further analyzed at the site-specific level in this Environmental Assessment. The impact analysis for the proposed activity focused on the geological and geophysical activities and the resources that may be potentially impacted. The impact producing factors (IPF) include: (1) active acoustic sound sources from airguns, (2) vessel noise, (3) vessel traffic, and (4) marine trash and debris.

In this SEA BOEM has considered three alternatives: (1) No Action; (2) Proposed Action as Submitted; and (3) Proposed Action with Conditions of Approval. BOEM has assessed the impacts of the proposed action on the following significant resources:

marine mammals;

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sea turtles; and fish.

The use of an active acoustic sound source (airgun) is potentially the most disruptive impact for a free-swimming individual or groups of marine mammals, turtles, and fish if they are in proximity to the airgun in operation. The effect of an active acoustic sound source is weighted most heavily out of all other potential impacting factors. Individual animals are vulnerable to injury if hit by the survey vessel from the proposed action. Conditions of approval include the monitoring of an exclusion zone by trained protected species observers and activation of survey shutdown requirements when mammals are observed: (1) within the exclusion zone or in proximity to an active acoustic sound source or (2) near the vessel. The application of passive acoustic monitoring, a visually/acoustically monitored exclusion zone, shutdown criteria, and vessel avoidance are designed to remove the possibility that animals and an operating airgun are located in the same place at the same time. Groups or individuals are therefore not unduly affected by underwater noise, or exposed to being hit by the survey vessel. Impact significance levels are explained in Chapter 3.1 of this SEA. Impacts from the proposed activities to marine mammals, sea turtles, and fish have been mitigated to negligible.

Our evaluation in this SEA has selected Alternative 3 and serves as the basis for approving the proposed action. BOEM concludes that no significant impacts are expected to occur to any affected resources by allowing the proposed action to proceed, provided that the specific conditions of approval and monitoring measures identified below are met by the operator.

COMPLIANCE WITH BIOLOGICAL OPINION TERMS AND CONDITIONS AND REASONABLE AND PRUDENT MEASURES: This approval is conditioned upon compliance with the Reasonable and Prudent Measures and implementing Terms and Conditions of the Biological Opinion issued by the National Marine Fisheries Service on March 13, 2020. This includes mitigation, particularly any appendices to Terms and Conditions applicable to the plan, as well as record-keeping and reporting sufficient to allow BOEM and BSEE to comply with reporting and monitoring requirements under the BO; and any additional reporting required by BOEM or BSEE developed as a result of BO implementation. The NMFS Biological Opinion may be found here: (https://www.fisheries.noaa.gov/resource/document/biological-opinion-federally-regulated-oil-and-gas-program-activities-gulf-mexico). The Appendices and protocols may be found here: (https://www.fisheries.noaa.gov/resource/document/appendices-biological-opinion-federally-regulated-oil-and-gas-program-gulf-mexico).

SUPPORT BASES AND VESSEL TRANSIT ROUTES: Approval of your plan is conditioned upon your use of the support bases and vessel transit routes as described in your plan. BOEM/BSEE must be notified at least 15 days prior to any vessel route changes that require transit of the Bryde's Whale area, and you must receive prior approval for that transit from BOEM/BSEE.

SEISMIC SURVEY OPERATION, MONITORING, AND REPORTING GUIDELINES: The applicant will follow the guidance provided under Appendix A: Seismic Survey Mitigation and Protected Species Observer Protocols found in the Biological Opinion issued by the National Marine Fisheries Service on March 13, 2020. The guidance can be accessed on NOAA Fisheries internet website at https://www.fisheries.noaa.gov/resource/document/appendices-biological-opinion-federally-regulated-oil-and-gas-program-gulf-mexico.

MARINE TRASH AND DEBRIS AWARENESS AND ELIMINATION: The applicant will follow the guidance provided under Appendix B. Gulf of Mexico Marine Trash and Debris Awareness and Elimination Survey Protocols found in the Biological Opinion issued by the National Marine Fisheries Service on March 13, 2020. The guidance can be accessed on NOAA Fisheries internet website at https://www.fisheries.noaa.gov/resource/document/appendices-biological-opinion-federally-regulated-oil-and-gas-program-gulf-mexico.

VESSEL-STRIKE AVOIDANCE/REPORTING: The applicant will follow the guidance provided under Appendix C. Gulf of Mexico Vessel Strike Avoidance and Injured/Dead Aquatic Protected Species Reporting Protocols found in the Biological Opinion issued by the National Marine Fisheries Service on March 13, 2020. The guidance can be accessed on the NOAA Fisheries

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internet site at https://www.fisheries.noaa.gov/resource/document/appendices-biological-opinion-federally-regulated-oil-and-gas-program-gulf-mexico.

SEA TURTLE RESUSCITATION GUIDELINES: The applicant will follow the guidance provided under Appendix J. Sea Turtle Handling and Resuscitation Guidelines found in the Biological Opinion issued by the National Marine Fisheries Service on March 13, 2020. The guidance can be accessed on the NOAA Fisheries internet site at https://www.fisheries.noaa.gov/resource/document/appendices-biological-opinion-federally-regulated-oil-and-gas-program-gulf-mexico.

SLACK-LINE PRECAUTIONS AND REPORTING REQUIREMENT: If operations require the use of flexible, small diameter (< 1 in) nylon, plastic, or fiber lines to support operations (with or without divers), operators/contractors must reduce the slack in the lines to prevent accidental entanglement of ESA-listed species. The following measures are required (noting that diver safety is paramount, and the following measures should be followed only in cases where they do not jeopardize human safety):

Operators must utilize tensioning tools and/or other appropriate procedures to reduce unnecessary looseness in the lines and/or potential looping.

The lines must remain taut.

A line tender must be present at all times during dive operations and must monitor the line(s) the entire time a diver is in the water.

Should the line tender and/or diver become aware of any ESA-listed species entanglement, the following protocols must be followed as soon as safety permits.

Should an ESA-listed species interaction resulting in entanglement, entrapment and/or injury occur, the interaction must be reported immediately or after diver safety (if present) is ensured. For assistance with marine mammals contact the number(s) below:

Marine Mammals Telephone

State Stranding Network Texas 800-962-6625 Louisiana 504-235-3005 Mississippi 888-767-3657 Alabama 877-942-5343 Florida 888-404-3922

* If you do not receive a response, go to the following website to ensure the listed number is correct: https://www.fisheries.noaa.gov/report

For assistance with sea turtles contact the number(s) below:

Sea Turtles Telephone

State Stranding Network Texas 361-949-8173 x 226 Louisiana 844-732-8785 Mississippi 228-369-4796 Alabama 866-732-8878 Florida 888-404-3922


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Assistance with other ESA-listed species (e.g., giant manta ray, oceanic whitetip shark, or Gulf sturgeon) should contact the ESA section 7 biologist at 301-427-8413 ([email protected]) and report all incidents to [email protected].

After the appropriate stranding networks have been contacted for assistance, you may call BSEE at 985-722-7902 for questions or additional guidance on recovery assistance needs (if still required), continued monitoring requirements, and incidental report information which at minimum is detailed below.

Within 24 hours of any event or observation, notify NMFS at [email protected] and BSEE at [email protected] with the following information:

1. Time, date, water depth, and location (latitude/longitude) of the first discovery of the interaction;

2. Name, type, and call sign of the vessel (or platform) in which the event occurred;

3. Species identification (if known) or description of the animal involved;

4. Condition of the animal during the event;

5. Photographs or video footage of the animal;

6. Stranding network line that was contacted for assistance; and

7. General narrative and timeline describing the events that took place.

MOON POOL MONITORING AND REPORTING: A moon pool has been identified during review of your plan submittal. If any sea turtle or other marine mammal is detected, you are required to contact NMFS at [email protected] and BSEE at [email protected] for additional guidance and incidental report information.

Moon pools with hull doors should attempt to keep doors closed when no activity is occurring within the moon pool, unless the safety of crew or vessel require otherwise. This will prevent animals from entering the confined area.

Use of a moon pool requires regular monitoring while open to the water column and if a vessel is not underway. Regular monitoring means 24-hour video monitoring with at hourly recurring checks for at least five minutes of the video feed, or at hourly recurring visual checks of the moon pool for at least five minutes by a dedicated crew observer with no other tasks during that visual check. If water conditions are such that observers are unable to see within a meter of the surface, operations requiring the lowering or retrieval of equipment through the moon pool should be conducted at a rate that will minimize potential harm, if safety permits.

Closing the hull door:

Should the moon pool have a hull door that can be closed, then prior to closure the moon pool must be monitored continuously by a dedicated crew observer with no other tasks, prior to closure and following closure to ensure that no individual ESA-listed species is trapped within the hull closed moon pool doors. If visibility is not clear to the hull door from above (e.g., turbidity or low light), 30 minutes of monitoring is required prior to hull door closure.

Movement of the vessel (without closed hull door) and equipment deployment/retrieval:

Prior to movement of the vessel and/or deployment/retrieval of equipment, the moon pool must be monitored continuously for a minimum of 30 minutes, by a dedicated crew observer with no other tasks, to ensure no ESA-listed species are present in the moon pool area.

If an ESA-listed species is observed in the moon pool, the vessel must not be moved and equipment must not be deployed or retrieved, to the extent practicable, unless the safety of crew or vessel requires otherwise. NMFS must be contacted immediately

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at [email protected]. If the observed animal leaves the moon pool, the operator may commence activities.

Should an ESA-listed species be observed in a moon pool prior to activity commencement, recovery of the animal or other actions specific to the scenario may be required to prevent interaction with the animal. Operators shall not take such action except at the direction of and after contact with NMFS.

Should an interaction with equipment or entanglement/entrapment of any ESA-listed species occur (e.g., the animal cannot or does not leave the moon pool on its own volition), the interaction must be reported immediately. Any observation of a leatherback sea turtle within a moon pool, regardless of whether interaction with equipment or entanglement/entrapment is observed, must be reported immediately to the ESA Section 7 biologist at 301-427-8413 ([email protected]). For minimum reporting information to include, see bullet list below.


Sea Turtles

Telephone

State Stranding Network

Texas 361-949-8173 x 226 Louisiana 844-732-8785 Mississippi 228-369-4796 Alabama 866-732-8878 Florida 888-404-3922


For assistance with marine mammals contact the number(s) below:

Marine Mammals

Telephone


Texas 800-962-6625 Louisiana 504-235-3005 Mississippi 888-767-3657 Alabama 877-942-5343 Florida 888-404-3922


Assistance with other ESA-listed species (e.g., giant manta ray, oceanic whitetip shark or Gulf sturgeon), contact the ESA Section 7 biologist at 301-427-8413 ([email protected]) and report all incidents to [email protected].


Within 24 hours of any event or observation within the moon pool, if not previously contacted for a specific interaction, notify NMFS at [email protected] and BSEE at [email protected] with the following information:


2. Name, type, and call sign of the vessel in which the event occurred;

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3. Size and location of moon pool within vessel (e.g., hull door or no hull door);

4. Equipment being utilized at time of interaction;


6. Approximate size of animal;



9. Stranding network line that was contacted for assistance;

10. General narrative and timeline describing the events that took place;

11. Whether activities in the moon pool were halted or changed upon observation of theanimal; and

12. Whether the animal remains in the pool at the time of the report, or if not, the time/date theanimal was last observed.

Conclusion: BOEM has evaluated the potential environmental impacts of the proposed action. Based on SEA No. R-7018, BOEM has determined that the proposed action would have no significant impact on the marine, coastal, and human environment provided that the avoidance and mitigation measures required by the specific conditions of approval are met by the operator. Therefore, an Environmental Impact Statement will not be required.

Chief, Environmental Operations Section, Date Office of the Environment New Orleans Office Bureau of Ocean Energy Management

September 21, 2020

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Table of Contents

Page

FINDING OF NO SIGNIFICANT IMPACT (FONSI) ................................................................................. i

1. PROPOSED ACTION ............................................................................................................................ 1 1.1. Background ................................................................................................................................. 2 1.2. Purpose of and Need for the Proposed Action ............................................................................ 2 1.3. Description of the Proposed Action ............................................................................................ 3

2. ALTERNATIVES CONSIDERED ........................................................................................................ 3 2.1. The No Action Alternative .......................................................................................................... 3 2.2. The Proposed Action as Submitted ............................................................................................. 3 2.3. The Proposed Action with Additional Conditions of Approval .................................................. 4 2.4. Summary and Comparison of the Alternatives ........................................................................... 4 2.5. Alternatives Considered but Not Analyzed in Detail .................................................................. 8

3. DESCRIPTION OF THE AFFECTED ENVIRONMENT AND ENVIRONMENTAL IMPACTS ..... 9 3.1. Introduction ................................................................................................................................. 9 3.2. Marine Mammals ...................................................................................................................... 11

3.2.1. Description ................................................................................................................. 11 3.2.2. Impact Analysis .......................................................................................................... 12 3.2.3. Cumulative Impact Analysis ...................................................................................... 20

3.3. Sea Turtles ................................................................................................................................ 20 3.3.1. Description ................................................................................................................. 20 3.3.2. Impact Analysis .......................................................................................................... 21 3.3.3. Cumulative Impact Analysis ...................................................................................... 24

3.4. Fish Resources and Essential Fish Habitat ................................................................................ 26 3.4.1. Description ................................................................................................................. 26 3.4.2. Impact Analysis .......................................................................................................... 27 3.4.3. Cumulative Impact Analysis ...................................................................................... 30

3.5. Other Considerations................................................................................................................. 30

4. CONSULTATION AND COORDINATION ...................................................................................... 30

5. BIBLIOGRAPHY ................................................................................................................................. 31

6. PREPARERS ........................................................................................................................................ 42

7. REVIEWERS ........................................................................................................................................ 42

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SITE-SPECIFIC ENVIRONMENTAL ASSESSMENT (SEA) PREPARED FOR

LLOG EXPLORATION OFFSHORE, L.L.C. REVISED EXPLORATION PLAN

NO. R-7018

1. INTRODUCTION LLOG Exploration Offshore, L.L.C. (LLOG) has submitted an ancillary application activities on the Outer Continental Shelf (OCS) of the Gulf of Mexico (GOM). This Site-Specific Environmental Assessment (SEA) evaluates the specific impacts associated with LLOG’s proposed ancillary activities. Chapter 1.3 of this SEA provides specific details on the ancillary activities proposed in LLOG’s Revised Exploration Plan (EP).

The SEA is tiered from:

Gulf of Mexico OCS Proposed Geological and Geophysical Activities Western, Central, and Eastern Planning Areas Final Programmatic Environmental Impact Statement (GOM G&G PEIS) (OCS EIS/EA BOEM 2017-051) (USDOI, BOEM, 2017a),

Gulf of Mexico OCS Oil and Gas Lease Sales: 2017-2022 Gulf of Mexico Lease Sales 249, 250, 251, 252, 253, 254, 256, 257, 259, and 261-Final Environmental Impact Statement (Multisale EIS) (OCS EIS/EA BOEM 2017-009) (USDOI, BOEM, 2017b),

Gulf of Mexico Lease Sale Final Supplemental Environmental Impact Statement 2018 (2018 SEIS) (OCS EIS/EA BOEM 2017-074) (USDOI, BOEM, 2017c),

Biological Opinion Oil and Gas Leasing, Exploration, Development, Production, Decommissioning, and All Related Activities in the Gulf of Mexico Outer Continental Shelf (FWS 2018 BO) (Issued by United States Fish and Wildlife Service [FWS] April 20, 2018); and

Biological Opinion on the Federally Regulated Oil and Gas Program Activities in the Gulf of Mexico (2020 BO) (Issued by National Marine Fisheries Service [NMFS] March 13, 2020).

“Tiering” is provided in the National Environmental Policy Act (NEPA) implementing regulations (40 CFR § 1502.20 and § 1508.28). It is designed to reduce and simplify the length of environmental assessments by eliminating repetitive discussions of impacts considered in prior NEPA compliance documents, allowing analyses to focus on those site-specific concerns and effects related to the action proposed. Document tiering in the Bureau of Ocean Energy Management (BOEM) is subject to additional guidance under the United States Department of the Interior (DOI) regulations at 43 CFR § 46.140 wherein the site-specific analysis must note which conditions and effects addressed in the programmatic document remain valid and which conditions and effects require additional review.

For this SEA, all of the analyses prepared in the GOM G&G PEIS, Multisale EIS, and 2018 SEIS, FWS 2018 BO, and NMFS 2020 BO are sufficiently comprehensive and adequate to support decisionmaking for LLOG’s proposed activities, with the following exceptions:

Active Acoustic Sound Sources and Vessel Noise and Traffic Impacts on Marine Mammals – the environmental baseline since completion of the programmatic analyses may have experienced slight changes and/or new information has become available;

Active Acoustic Sound Sources and Vessel Noise and Traffic Impacts on Sea Turtles – the environmental baseline since completion of the programmatic analyses may have experienced slight changes and/or new information has become available; and

Active Acoustic Sound Sources Impacts on Fish and Fisheries – the environmental baseline since completion of the programmatic analyses may have experienced slight changes and/or new information has become available.

Marine mammals, sea turtles, fish, and commercial and recreational fisheries, as indicated in the GOM G&G PEIS, are susceptible to impacts from geophysical activities that may be considered adverse, but not significant. Impacts to fishes and commercial and recreational fisheries from the proposed activities are

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not expected due to the temporary nature of the operations. This SEA considers the potential for change in the status of resources and the potential for increased sensitivity of those resources to impacts from ancillary activities.

Therefore, Chapter 3 of this SEA will focus on how the new information relative to the cumulative environmental effects of this action. Where applicable, relevant affected environment discussions and impact analyses from the GOM G&G PEIS, Multisale EIS, 2018 SEIS, FWS 2018 BO, and NMFS 2020 BO are summarized and utilized for this site-specific analyses, and are incorporated by reference into this SEA. Relevant conditions of approval and monitoring measures identified in the previous GOM G&G PEIS, Multisale EIS, 2018 SEIS, FWS 2018 BO, and NMFS 2020 BO have been considered in the evaluation of the proposed action.

1.1. BACKGROUND BOEM and the Bureau of Safety and Environmental Enforcement (BSEE) are mandated to manage the development of OCS oil, gas, mineral resources, and renewable energy resources while ensuring safe operations and the protection of the human, marine, and coastal environments. One purpose of BOEM’s regulatory program is to ensure that the G&G data is obtained in an environmentally safe manner. BOEM and BSEE regulate leasing, exploration, development, production, and decommissioning, and they perform environmental analyses during each of these phases. BOEM’s Resource Evaluation Program oversees “speculative” G&G data acquisition and permitting activities pursuant to 30 CFR § 551 and § 580. Specifically, 30 CFR § 551 regulates prelease G&G exploratory operations for oil, gas, and sulfur resources, and 30 CFR § 580 regulates prelease prospecting activities. BOEM’s Office of Leasing and Plans oversees “on-lease” or “ancillary” G&G and data acquisition pursuant to 30 CFR § 550, which applies to postlease G&G exploratory operations, such as those proposed by the applicant.

The G&G surveys provide information used by industry and government to evaluate the potential for offshore oil and gas resources, renewable energy development, mineral resources exploration and development, and geologic hazards in a particular area. Industry needs accurate data to determine the location, extent, and properties of hydrocarbon resources. Information on shallow geologic hazards and seafloor geotechnical properties assists in the safe and economical exploration, development, production, and transportation of hydrocarbons. Additionally, the results of G&G surveys characterize sea bottom conditions before installing a renewable energy facility or to verify the completion of decommissioning activities.

The scope of the effects on GOM resources from activities proposed in LLOG’s Revised EP, No. R-7018, were fully discussed and analyzed in the GOM G&G PEIS. Neither the specific location, equipment, nor the duration of this proposal will result in impacts different from those discussed in the GOM G&G PEIS, Multisale EIS, 2018 SEIS, FWS 2018 BO, or NMFS 2020 BO prepared since that time. Existing peer-reviewed literature and environmental monitoring suggests the proposed activity will not result in a different cumulative impact conclusion from what was made in the GOM G&G PEIS, Multisale EIS, 2018 SEIS, FWS 2018 BO, or NMFS 2020 BO. This information was not available or considered during the preparation of the GOM G&G PEIS. Therefore, this SEA was prepared by BOEM to evaluate the operator’s proposed ancillary activities in light of any new changes in the baseline and/or new information.

1.2. PURPOSE OF AND NEED FOR THE PROPOSED ACTION LLOG has submitted R-7018 to conduct an ancillary activity on the OCS. The purpose of the proposed action is to conduct a zero-offset, offset, or walkaway vertical seismic profile (VSP), salt proximity survey, and/or checkshot survey using airguns. This information can be utilized to evaluate the potential for, and develop plans for, the development and production of hydrocarbon resources on the OCS, which would help satisfy the Nation’s need for energy. Additional information regarding other survey activities can be found in Appendix F of the GOM G&G PEIS.

The need for this action is established by BOEM's responsibility under the Outer Continental Shelf Lands Act (OCSLA) to make OCS lands available for expeditious and orderly development, subject to environmental safeguards, in a manner that is consistent with the maintenance of competition and other national needs. Section 11 of the OCSLA, 43 U.S.C. 1340, requires anyone seeking to conduct such activities to first obtain approval from BOEM. The Secretary of the Interior oversees the OCS oil and gas

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program, and BOEM and BSEE are the agencies charged with this oversight and regulated management of the permitted or otherwise authorized oil and gas activities. The Secretary is required to balance orderly resource development with protection of the human, marine, and coastal environments while ensuring that the U.S. public receives a fair return for resources discovered on and produced from public lands (43 U.S.C. 1332[3]).

In response to the proposed action in LLOG’s plan, BOEM has regulatory responsibility, consistent with the OCSLA and other applicable laws, to approve, approve with modifications or conditions of approval, or deny the application. BOEM’s regulations provide criteria that BOEM will apply in reaching a decision and providing for any applicable conditions of approval.

1.3. DESCRIPTION OF THE PROPOSED ACTION LLOG proposes proposes to conduct a zero-offset, offset, or walkaway VSP, salt proximity survey, and/or checkshot survey with an airgun array that will either be deployed form the deck of the Botruc 41 offshore supply vessel, or mounted from the Seadrill West Neptune rig crane. The receivers for the survey will be deployed in the Well 001 ST00PB00 wellbore. No streamers or source vessels will be used during the survey. The proposed activity is located south of Louisiana in the Central Planning Area of the GOM. The well is located in Ewing Bank Block 921; lease OCS G 36704 and 35295, and the survey area also includes Ewing Bank Block 877, Lease Number G-35295. The area of the proposed action is approximately 67 miles (mi) (108 kilometers [km]) from the nearest shoreline. The water depth of the entire survey area in Ewing Bank ranges from 925 – 1,860 feet (ft) (282 - 567 meters (m)). The operation will be using support vessels whose operations are comparable to that described in the GOM G&G PEIS for similar activities. Site-specific analysis was completed using LLOG’s description of the proposed operations; however, specific technical information regarding the G&G activities described in the plan is proprietary and therefore not included in this document. The proposed survey is expected to take approximately 2 days to complete and will begin between October and December 2020 (LLOG, 2020).

Airguns

The sound source typically used in most seismic surveys is an airgun array. An airgun array consists of pneumatic devices that produce acoustic output through the rapid release of a volume of compressed air. The airgun array is designed to direct the high energy bursts of low-frequency sound (termed a “shot”) downward toward the seafloor. Reflected sounds from below the seafloor are received by an array of sensitive hydrophones on cables (collectively termed “streamers”) that are either towed behind a survey vessel, attached to cables/nodes placed on or anchored to the seafloor, or placed within the wellbore during VSP surveys. A typical full-scale array produces a source level of 248-255 dB re µPa-m, zero-to-peak (referring to the waveform of the sound pulse). Typical seismic arrays being used in the GOM produce source levels (sound pressure levels) of approximately 240 dB re 1 µPa @ 1 m. While the seismic array pulses are directed toward the ocean bottom, sound can propagate horizontally for several kilometers (Richardson et al., 1995). Measurements of sources at sea (Goold and Fish, 1998; Sodal, 1999) have demonstrated that, although airgun arrays are primarily a source of low-frequency energy, there is also some transmission of energy at higher frequencies. These energies encompass the entire audio frequency range of 20 Hz to 20 kHz (Goold and Fish, 1998) and may extend well into the ultrasonic range up to 50 kHz (Sodal, 1999).

2. ALTERNATIVES CONSIDERED

2.1. NO ACTION ALTERNATIVE Alternative 1 – If this alternative is selected the applicant would not undertake the proposed activity. This alternative might prevent the exploration and development of hydrocarbons, resulting in the potential loss of royalty income and energy resources for the United States.

2.2. PROPOSED ACTION AS SUBMITTED Alternative 2 – If this alternative is selected the applicant would undertake the proposed activity as requested in the application. No additional conditions of approval would be required by BOEM.

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2.3. PROPOSED ACTION WITH ADDITIONAL CONDITIONS OF APPROVAL Alternative 3 – This is BOEM’s Preferred Alternative. If this alternative is selected the applicant would undertake the proposed activity, as requested in the application, but with the conditions of approval identified by BOEM, in coordination with NMFS and in accordance with the NMFS 2020 BO (listed in Chapter 2.4 below and described in the effects analyses), to fully address the site- and project-specific impacts of the proposed action.

2.4. SUMMARY AND COMPARISON OF THE ALTERNATIVES If selected, Alternative 1, the No Action Alternative, would prevent the applicant from acquiring the proper permits and the subsequent collection of seismic data on the OCS. If the survey is not deployed, the opportunity for LLOG to efficiently and expeditiously develop their lease may be forfeited. Alternative 1 would not result in any impacts to the environmental resources analyzed in Chapter 3, but it does not meet the underlying purpose and need.

If selected, Alternative 2 would allow for the collection of seismic data, as requested in the plan, but would not include any additional conditions of approval or monitoring measures applied by BOEM or NMFS. Alternative 2 meets the underlying purpose and need of the proposed action but could cause unacceptable impacts to the environmental resources analyzed, as described in Chapter 3 (e.g., hearing loss in marine mammals, injuries to marine mammals and sea turtles from vessel strikes).

Alternative 3 is the Preferred Alternative, based on the analysis of potential impacts to resources described in Chapter 3, because it meets the underlying purpose and need, and also implements conditions of approval and monitoring requirements that adequately limit or negate potential impacts. Implementation of these standard conditions of approval and monitoring measures was assumed as part of the analysis in the NMFS 2020 Endangered Species Act (ESA) Section 7 Biological Opinion (BO) and BOEM is committed to requiring their implementation. NMFS provided a response to the Step-Down Review of R-7018 on September 15, 2020, in that with implementation of the mitigation and monitoring measures below, the proposed activities are within the scope of NMFS effects analysis considered for the most recent BO. The survey activities proposed will provide LLOG with sufficiently accurate data to determine the location, extent, and properties of potential hydrocarbon resources. Additionally, the collected data supports BOEM’s regulatory and oversight responsibilities while promoting the development of hydrocarbon resources, potentially resulting in increased royalty income as well as energy resources for the United States.

Other alternatives regarding Agency oversight of the G&G permitting program, identified in Chapter 2 of the GOM G&G PEIS, were reviewed with the alternatives listed above chosen as reasonable for the current proposed action.

Conditions of Approval Required under the Preferred Alternative

The need for and utility of the following conditions of approval and monitoring measures are discussed in the relevant impact analysis sections of this SEA. The following conditions of approval and reporting requirements were identified to ensure adequate environmental protection and post-activity compliance:

COMPLIANCE WITH BIOLOGICAL OPINION TERMS AND CONDITIONS AND REASONABLE AND PRUDENT MEASURES: This approval is conditioned upon compliance with the Reasonable and Prudent Measures and implementing Terms and Conditions of the Biological Opinion issued by the National Marine Fisheries Service on March 13, 2020. This includes mitigation, particularly any appendices to Terms and Conditions applicable to the plan, as well as record-keeping and reporting sufficient to allow BOEM and BSEE to comply with reporting and monitoring requirements under the BO; and any additional reporting required by BOEM or BSEE developed as a result of BO implementation. The NMFS Biological Opinion may be found here: (https://www.fisheries.noaa.gov/resource/document/biological-opinion-federally-regulated-oil-and-gas-program-activities-gulf-mexico). The Appendices and protocols may be found here: (https://www.fisheries.noaa.gov/resource/document/appendices-biological-opinion-federally-regulated-oil-and-gas-program-gulf-mexico).

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SUPPORT BASES AND VESSEL TRANSIT ROUTES: Approval of your plan is conditioned upon your use of the support bases and vessel transit routes as described in your plan. BOEM/BSEE must be notified at least 15 days prior to any vessel route changes that require transit of the Bryde's Whale area, and you must receive prior approval for that transit from BOEM/BSEE.

SEISMIC SURVEY OPERATION, MONITORING, AND REPORTING GUIDELINES: The applicant will follow the guidance provided under Appendix A: Seismic Survey Mitigation and Protected Species Observer Protocols found in the Biological Opinion issued by the National Marine Fisheries Service on March 13, 2020. The guidance can be accessed on NOAA Fisheries internet website at https://www.fisheries.noaa.gov/resource/document/appendices-biological-opinion-federally-regulated-oil-and-gas-program-gulf-mexico.

MARINE TRASH AND DEBRIS AWARENESS AND ELIMINATION: The applicant will follow the guidance provided under Appendix B. Gulf of Mexico Marine Trash and Debris Awareness and Elimination Survey Protocols found in the Biological Opinion issued by the National Marine Fisheries Service on March 13, 2020. The guidance can be accessed on NOAA Fisheries internet website at https://www.fisheries.noaa.gov/resource/document/appendices-biological-opinion-federally-regulated-oil-and-gas-program-gulf-mexico.

VESSEL-STRIKE AVOIDANCE/REPORTING: The applicant will follow the guidance provided under Appendix C. Gulf of Mexico Vessel Strike Avoidance and Injured/Dead Aquatic Protected Species Reporting Protocols found in the Biological Opinion issued by the National Marine Fisheries Service on March 13, 2020. The guidance can be accessed on the NOAA Fisheries internet site at https://www.fisheries.noaa.gov/resource/document/appendices-biological-opinion-federally-regulated-oil-and-gas-program-gulf-mexico.

SEA TURTLE RESUSCITATION GUIDELINES: The applicant will follow the guidance provided under Appendix J. Sea Turtle Handling and Resuscitation Guidelines found in the Biological Opinion issued by the National Marine Fisheries Service on March 13, 2020. The guidance can be accessed on the NOAA Fisheries internet site at https://www.fisheries.noaa.gov/resource/document/appendices-biological-opinion-federally-regulated-oil-and-gas-program-gulf-mexico.

SLACK-LINE PRECAUTIONS AND REPORTING REQUIREMENT: If operations require the use of flexible, small diameter (< 1 in) nylon, plastic, or fiber lines to support operations (with or without divers), operators/contractors must reduce the slack in the lines to prevent accidental entanglement of ESA-listed species. The following measures are required (noting that diver safety is paramount, and the following measures should be followed only in cases where they do not jeopardize human safety):

Operators must utilize tensioning tools and/or other appropriate procedures to reduce unnecessary looseness in the lines and/or potential looping.

The lines must remain taut.

A line tender must be present at all times during dive operations and must monitor the line(s) the entire time a diver is in the water.

Should the line tender and/or diver become aware of any ESA-listed species entanglement, the following protocols must be followed as soon as safety permits.

Should an ESA-listed species interaction resulting in entanglement, entrapment and/or injury occur, the interaction must be reported immediately or after diver safety (if present) is ensured. For assistance with marine mammals contact the number(s) below:

Marine Mammals

Telephone

State Stranding Network Texas 800-962-6625 Louisiana 504-235-3005

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Mississippi 888-767-3657 Alabama 877-942-5343 Florida 888-404-3922



Sea Turtles

Telephone

State Stranding Network Texas 361-949-8173 x 226 Louisiana 844-732-8785 Mississippi 228-369-4796 Alabama 866-732-8878 Florida 888-404-3922


Assistance with other ESA-listed species (e.g., giant manta ray, oceanic whitetip shark, or Gulf sturgeon) should contact the ESA section 7 biologist at 301-427-8413 ([email protected]) and report all incidents to [email protected].


Within 24 hours of any event or observation, notify NMFS at [email protected] and BSEE at [email protected] with the following information:


2. Name, type, and call sign of the vessel (or platform) in which the event occurred;




6. Stranding network line that was contacted for assistance; and

7. General narrative and timeline describing the events that took place.

MOON POOL MONITORING AND REPORTING: A moon pool has been identified during review of your plan submittal. If any sea turtle or other marine mammal is detected, you are required to contact NMFS at [email protected] and BSEE at [email protected] for additional guidance and incidental report information.

Moon pools with hull doors should attempt to keep doors closed when no activity is occurring within the moon pool, unless the safety of crew or vessel require otherwise. This will prevent animals from entering the confined area.

Use of a moon pool requires regular monitoring while open to the water column and if a vessel is not underway. Regular monitoring means 24-hour video monitoring with at hourly recurring checks for at least five minutes of the video feed, or at hourly recurring visual checks of the moon pool for at least five minutes by a dedicated crew observer with no other tasks during that visual check. If water conditions are such that observers are unable to see within a meter of the surface, operations

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requiring the lowering or retrieval of equipment through the moon pool should be conducted at a rate that will minimize potential harm, if safety permits.

Closing the hull door:

Should the moon pool have a hull door that can be closed, then prior to closure the moon pool must be monitored continuously by a dedicated crew observer with no other tasks, prior to closure and following closure to ensure that no individual ESA-listed species is trapped within the hull closed moon pool doors. If visibility is not clear to the hull door from above (e.g., turbidity or low light), 30 minutes of monitoring is required prior to hull door closure.

Movement of the vessel (without closed hull door) and equipment deployment/retrieval:

Prior to movement of the vessel and/or deployment/retrieval of equipment, the moon pool must be monitored continuously for a minimum of 30 minutes, by a dedicated crew observer with no other tasks, to ensure no ESA-listed species are present in the moon pool area.

If an ESA-listed species is observed in the moon pool, the vessel must not be moved and equipment must not be deployed or retrieved, to the extent practicable, unless the safety of crew or vessel requires otherwise. NMFS must be contacted immediately at [email protected]. If the observed animal leaves the moon pool, the operator may commence activities.

Should an ESA-listed species be observed in a moon pool prior to activity commencement, recovery of the animal or other actions specific to the scenario may be required to prevent interaction with the animal. Operators shall not take such action except at the direction of and after contact with NMFS.

Should an interaction with equipment or entanglement/entrapment of any ESA-listed species occur (e.g., the animal cannot or does not leave the moon pool on its own volition), the interaction must be reported immediately. Any observation of a leatherback sea turtle within a moon pool, regardless of whether interaction with equipment or entanglement/entrapment is observed, must be reported immediately to the ESA Section 7 biologist at 301-427-8413 ([email protected]). For minimum reporting information to include, see bullet list below.


Sea Turtles

Telephone


Texas 361-949-8173 x 226 Louisiana 844-732-8785 Mississippi 228-369-4796 Alabama 866-732-8878 Florida 888-404-3922


For assistance with marine mammals contact the number(s) below:

Marine Mammals

Telephone


Texas 800-962-6625 Louisiana 504-235-3005 Mississippi 888-767-3657 Alabama 877-942-5343

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Florida 888-404-3922 * If you do not receive a response, go to the following website to ensure the listed number is correct: https://www.fisheries.noaa.gov/report

Assistance with other ESA-listed species (e.g., giant manta ray, oceanic whitetip shark or Gulf sturgeon), contact the ESA Section 7 biologist at 301-427-8413 ([email protected]) and report all incidents to [email protected].


Within 24 hours of any event or observation within the moon pool, if not previously contacted for a specific interaction, notify NMFS at [email protected] and BSEE at [email protected] with the following information:


2. Name, type, and call sign of the vessel in which the event occurred;

3. Size and location of moon pool within vessel (e.g., hull door or no hull door);

4. Equipment being utilized at time of interaction;


6. Approximate size of animal;



9. Stranding network line that was contacted for assistance;

10. General narrative and timeline describing the events that took place;

11. Whether activities in the moon pool were halted or changed upon observation of the animal; and

12. Whether the animal remains in the pool at the time of the report, or if not, the time/date the animal was last observed.

2.5. ALTERNATIVES CONSIDERED BUT NOT ANALYZED IN DETAIL A viable alternative is required to be a logical option for carrying out the proposed action, ensure that the purpose of and need can be met, and be feasible under the regulatory directives of the OCSLA and all other applicable guidance. As such, other alternatives regarding Agency oversight of the G&G permitting program, identified in Chapter 2 of the GOM G&G PEIS, were reviewed with the alternatives listed above chosen as reasonable for the current proposed action. Several other alternatives were considered and reviewed during the coordination of the resource reviews, but they were ultimately dismissed and not analyzed further since they did not meet the aforementioned requirements. The following alternative was considered and given review; however, it was not accepted for the reasons discussed below.

Alternative Requiring Shut-Down Conditions for Delphinids

This analysis also considered whether to apply the shutdown conditions to delphinids. From a biological standpoint, the best available information suggests that delphinids are considered mid-frequency specialists (i.e., auditory bandwidth of 150 Hz to 160 kHz) (Southall et al., 2007). Low frequency seismic arrays, such as the one considered for use under this proposed action, generally operate in the frequency range of 20 Hz to 20 kHz (Goold and Fish, 1998) and may extend well into the ultrasonic range up to 50 kHz (Sodal, 1999). Therefore, while the majority of the seismic noise occurs at frequencies below that of delphinids, there are some components that may enter into the hearing range of delphinids (Goold and Fish, 1998). These higher

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frequency components would be at lower intensity levels (i.e., not as loud). It is unclear, though, from a scientific standpoint whether any of the seismic noise that might be heard by delphinids is in fact disruptive.

Delphinids are known to bow ride on operating seismic vessels. BOEM funded a data synthesis study on the effectiveness of seismic survey conditions of approval and marine mammal observer reports (USDOI, BOEM, 2012) that analyzed protected species observer (PSO) data collected from 2002-2008 in the GOM. Approximately 58 percent of all dolphin sightings, occurred within the 500 m exclusion zone, and of these, 33 percent were exhibiting bow-riding behavior.

Looking at these records for a typical year (2009), approximately 400 (~27 %) were delphinids within the 500 meter exclusion zone with operating airguns. In that same year, there were 55 records of shut downs for whales within the 500 m exclusion zone. If sources had also been shut down for the 400 sightings of delphinids, this would have resulted in a 7-fold increase in the number of shutdowns. There is little doubt then that a shut-down provision for delphinids within the exclusion zone would have a significant impact on seismic operations, such as those under the proposed action.

BOEM next considered whether a provision could be applied to allow for a reasonable exception for bow riding delphinids. For example, a provision could be considered that would allow PSOs to call for a power down (versus immediate shut down) of the seismic source to the smallest airgun should any delphinid enter, or come close to entering, the 500 meter exclusion zone referenced under Definitions of Appendix A: Seismic Survey Mitigation and Protected Species Observer Protocols in the NMFS 2020 BO. If the delphinid(s) leave the exclusion zone or engage in bow riding behavior then the PSO could call for the immediate return of the array to full power. This would allow for an opportunity for the PSO to determine if the behavior of the animal(s) warranted a shut down and if not would allow the applicant to return to full power more quickly (versus a shut down followed by a 30 minute clearance of the zone and a 20-40 minute ramp up procedure).

Based on the PSO sighting records, it is clear that shut downs for delphinids would result in an impact to industry activities. Unlike other sound producing activities (e.g., sonar), seismic surveys occur on specified tracklines that need to be followed in order to meet the data quality objectives of the survey. In other words, seismic vessels in operation cannot simply divert away from nearby marine mammals without a loss in data quality. As stated above, an analysis of 2009 PSO data (USDOI, BOEM, 2012) indicate that if shut downs for delphinids within the exclusion zone were employed there would have been a 7-fold increase in shut downs of seismic arrays that year. Shut downs of 30 minutes or longer would have required an additional 30 minute observation period to ensure animals have left the exclusion area followed by a 20-40 minute ramp up procedure. In all likelihood, these shut downs would then have required the applicants to return to an earlier point in the track line and resurvey the area again. This not only results in substantially more expense in down time and repositioning of seismic arrays and streamers, but would also likely increase the duration of and amount of total seismic noise for each affected survey area.

Conclusion

Based on the analysis above, BOEM believes it is essential to more fully investigate and vet the application of shut down conditions to delphinids before requiring it as a condition of approval in the GOM (under Alternative 3) or considering it as an additional alternative to the proposed action. It is BOEM’s intention, therefore, to fully analyze the application of this condition of approval.

3. DESCRIPTION OF THE AFFECTED ENVIRONMENT AND ENVIRONMENTAL IMPACTS

3.1. INTRODUCTION The discussion below will: (1) describe/summarize the pertinent potentially affected resources; (2) determine whether the proposed survey activities and their impact-producing factors (IPF) will have significant impacts on the marine, coastal, or human environments of the GOM; and (3) identify significant impacts, if any, that may require further NEPA analysis in an EIS. The description of the affected environment and impact analysis are presented together in this section for each resource.

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For each potentially affected resource, BOEM staff reviewed and analyzed all currently available peer-reviewed literature and integrated these data and findings into the analyses below. The analyses cite the best available, relevant scientific literature. BOEM performed this analysis to determine whether LLOG’s proposed survey activities will significantly impact the marine, coastal, or human environments of the GOM. For the impact analysis, resource-specific significance criteria were developed for each category of the affected environment. The criteria reflect consideration of both the context and intensity of the impact at issue (see 40 CFR § 1508.27). The criteria for impacts to environmental resources are classified into one of the three following levels:

Significant Adverse Impact (including those that could be mitigated to nonsignificance); Adverse but Not Significant Impact; or Negligible Impact.

Preliminary screening for this assessment was based on a review of this relevant literature; previous SEAs; the GOM G&G PEIS (USDOI, BOEM, 2017a); Multisale EIS (USDOI, BOEM, 2017b); 2018 SEIS (USDOI, BOEM, 2017c); the NMFS 2020 BO (USDOC, NMFS, 2020a); and relevant literature pertinent to historic and projected activities. BOEM initially considered the following resources for impact analysis:

marine mammals (including Endangered Species Act [ESA] listed species and strategic stocks); sea turtles (all are ESA listed species); fishes (including listed species and ichtyoplankton); commercial and recreational fisheries; coastal and marine birds (including ESA listed species); benthic communities; archaeological resources; military uses; recreational and commercial diving; marine transportation; geology/sediments; and air and water quality.

In the GOM G&G PEIS, the impact analysis focused on a broad group of G&G activities (including other survey types) and resources with the potential for non-negligible impacts. First, a matrix identifies impact agents associated with each type of G&G activity (Chapter 3 of the GOM G&G PEIS; USDOI, BOEM, 2017a). The IPFs include: (1) active acoustic sound sources; (2) vessel and equipment noise; (3) vessel traffic; (4) aircraft traffic and noise; (5) stand-off distance; (6) vessel discharges; (7) trash and debris; (8) seafloor disturbance; (9) drilling discharges; (10) entanglement; and (11) accidental fuel spills. The preliminary analysis in the GOM G&G PEIS considers surveys of the type proposed by LLOG as well as impacts to resources by type of activity. To assist with subsequent coordination, the GOM G&G PEIS’s analysis broadly defined the level of impact associated with each impact-level as follows:

Nominal: little or no measurable/detectable impact;

Minor: impacts are detectable, short term, extensive or localized, but less than severe;

Moderate: impacts are detectable, short term, extensive, and severe; or impacts are detectable, short term or long lasting, localized, and severe; or impacts are detectable, long lasting, extensive or localized, but less than severe; and

Major: impacts are detectable, long lasting, extensive, and severe.

The GOM G&G PEIS notes that G&G surveys have historically covered a large area of the GOM each year and, when unmitigated, have the greatest potential for “significant” impacts on protected and other sensitive marine species in comparison with other OCSLA-approved activities, including, but not limited to, exploration and development drilling. Further, it acknowledges increasing concerns in the regulatory and scientific communities regarding acoustic impacts on marine life, including marine mammals, turtles, and

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fishes. Species of particular concern are those whose hearing capabilities (based on vocalization characteristics) fall within the low frequencies introduced into the marine environment by G&G activities. The GOM G&G PEIS provides a comprehensive characterization of biological resources that may be adversely affected by G&G activities. This information is summarized in the various resource-specific descriptions of the affected environment and impact analyses in the chapters that follow.

However, for the purposes of this SEA, BOEM has not included analyses on resource areas that were evaluated and considered under the GOM G&G PEIS as having nominal impacts (see 40 CFR §1508.27) or determined the resource would not be impacted by the proposed action. Such a procedure is consistent with the NEPA concept of tiering (40 CFR §1502.20). Additionally, since no expansion or modification of support bases or related vessel construction work are proposed as a result of this activity, socioeconomic effects were not analyzed due to the type, the temporary nature, and employment size of the survey activity. The most recent evaluation of the best available peer-reviewed scientific literature continues to support this conclusion for the following resource categories:

commercial and recreational fisheries; coastal and marine birds (including ESA listed species); benthic communities; archaeological resources; military uses; recreational and commercial diving; marine transportation; geology/sediments; and air and water quality.

For this SEA, BOEM evaluated the potential impacts from the operator’s proposed G&G activities for the following resource categories:

marine mammals (including threatened/endangered and non-ESA listed species); sea turtles (all are ESA listed species); and fish and fisheries (including listed species and ichtyoplankton).

3.2. MARINE MAMMALS

3.2.1. Description

The marine mammal community is diverse and distributed throughout the northern GOM waters. The GOM’s marine mammals are represented by members of the taxonomic order Cetacea, including suborders Mysticeti (i.e., baleen whales) and Odontoceti (i.e., toothed whales), as well as the order Sirenia (i.e., manatee). Twenty-one species of cetaceans and one species of Sirenia regularly occur in the GOM and are identified in the NMFS Stock Assessment Reports (SAR) (Jefferson et al., 2008; Davis et al., 2000; Roberts et al., 2016; Hayes et al., 2018; Hayes et al., 2019). A complete description of marine mammals can be found in Chapter 4.9 of the Multisale EIS and 2018 SEIS, in the NMFS 2017 and 2018 SAR (Hayes et al., 2018 and 2019), and in the NMFS 2020 BO (USDOC, NMFS, 2020a), and are incorporated by reference.

Threatened or Endangered Marine Mammal Species

Only two cetaceans, the sperm whale (Physeter macrocephalus) and the GOM Bryde’s whale (Balaenoptera edeni), regularly occur in the GOM and are listed as endangered under the ESA. On January 8, 2016 (81 FR 999), the United States Fish and Wildlife Service (FWS) issued a proposed rule and notice to reclassify the West Indian manatee from endangered to threatened (Federal Register, 2016) which was later issued as a Final Rule (82 FR 16668) on April 5, 2017 (Federal Register, 2017). On December 2, 1970, in the Final Rule (35 FR 18319), the sperm whale was listed as endangered throughout its range. The Final Rule (84 FR 15446) to list the GOM Bryde’s whale as endangered was issued and became effective on May 15, 2019 (Federal Register, 2019). The only commonly occurring baleen whale in the northern GOM is the Bryde’s whale. Most sightings have been made in the De Soto Canyon region and off western

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Florida, although there have been some in the west-central portion of the northeastern GOM. The best estimate of abundance for Bryde’s whales in the northern GOM is 33 individuals, which is the last estimate from a 2009 survey (Hayes et al., 2018). Sperm whales in the GOM are not evenly distributed, showing greater densities in areas associated with oceanic features that provide the best foraging opportunities (USDOC, NMFS, 2020a).

Non-ESA-Listed Marine Mammal Species

Nineteen toothed cetaceans (including beaked whales and dolphins) regularly occur in the GOM but are not ESA-listed. Despite being non-listed, the Marine Mammal Protection Act (MMPA) of 1972 protects all marine mammals.

Unusual Mortality Events (UME)

An UME is defined under the MMPA as a “stranding that is unexpected, involves a significant die-off of any marine mammal population, and demands immediate response.” A list of active and closed UMEs with updated information can be found at the following website: https://www.fisheries.noaa.gov/national/marine-life-distress/active-and-closed-unusual-mortality-events.

2018-2020 Southwest Florida Bottlenose Dolphin UME (UME 66)

Since July 2018, the 2018-2020 Southwest Florida Bottlenose Dolphin UME was issued because of elevated bottlenose dolphin mortalities. Southwest Florida has been experiencing an ongoing severe bloom of a red tide organism since November 2017. The results from several necropsies showed positive findings of red tide toxin (brevetoxin) indicating this UME is related to the bloom. Other species such as fish, sea turtles, and manatees have also been impacted by the algal bloom (USDOC, NMFS, 2020b). This UME and its associated investigation are on-going.

Marine Mammal Hearing

All marine mammals produce and use sound to communicate with another animal of the same species, to navigate and sense their environment, to locate and capture prey, and to detect and avoid predators (Southall et al., 2007 and 2019). The hearing of marine mammals varies based on individuals, absolute threshold of the species, masking, localization, frequency discrimination, and the motivation to be sensitive to a sound (Richardson et al., 1995). Southall et al. (2007) described the frequency sensitivity in five functional hearing groups of marine mammals by combining behavioral and electrophysiological audiograms with comparative anatomy, modeling, and response measured in ear tissues, which has been updated by Southall et al. (2019) to include six proposed hearing groups. For potentially affected marine mammal species in the GOM, the main functional hearing groups include: (1) low-frequency cetaceans with an estimated auditory bandwidth of 7 Hz to 35 kHz; (2) mid-frequency cetaceans with functional hearing of approximately 150 Hz to 160 kHz; and (3) high-frequency cetaceans with functional hearing estimated from 275 Hz to 180 kHz. These hearing sensitivity and frequency ranges are based on audiograms that are obtained by either: (1) behavioral testing on captive, trained animals; or (2) electrophysiological or auditory evoked potential (AEP) methods (Richardson et al., 1995). Currently, there are no behavioral or AEP audiograms for low-frequency cetaceans available. Audiograms, both behavioral and AEP, are available for some mid-frequency and high-frequency cetaceans (Richardson et al., 1995; Nedwell et al., 2004; Southall et al., 2007 and 2019; Au and Hastings, 2008).

3.2.2. Impact Analysis

The IPFs associated with the proposed action that could affect both ESA-listed and non-ESA-listed marine mammals are primarily active acoustic sound sources and vessel noise from survey activities, collisions with seismic survey vessels, and marine trash and debris. Chapter 4.2 of the GOM G&G PEIS contains a discussion of the potential impacts from survey operations on marine mammal resources (USDOI, BOEM, 2017a). Additional information about routine impacts from oil and gas activity on impacts on marine mammals is addressed in Chapter 4.9 of the Multisale EIS and 2018 SEIS and the NMFS 2020 BO issued March 13, 2020. The discussions are summarized below and are incorporated by reference into this SEA. The best available scientific information also indicates that seismic airgun noise may affect non-ESA-listed marine mammal species (Southall et al., 2007 and 2019).

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3.2.2.1. Alternative 1

If Alternative 1, the No Action Alternative, is selected the applicant would not undertake the proposed activities; therefore, the IPFs to marine mammals would not occur. For example, there would be no vessel noise or seismic airgun noise that would result in behavioral change, masking, or non-auditory effects to marine mammals, no long-term or permanent displacement of the animals from preferred habitats, and no destruction or adverse modification of any habitats. In addition, there would be no survey related debris that could result in endangerment to marine mammals and no additional vessel traffic related to the survey activities, there would be no risk of collisions with marine mammals.


If Alternative 2, the Proposed Action, is selected the applicant would undertake the proposed activities, as requested and conditioned in the application. Examples of potential impacts to marine mammals without implementation of the above referenced conditions of approval and monitoring measures include, but are not limited to: injury from vessel strikes, hearing loss from seismic noise, disruption of feeding and other behaviors from seismic noise and vessel presence. This Alternative would not adequately limit or negate potential impacts to marine mammals.


If Alternative 3, the Proposed Action with Additional Conditions of Approval, is selected the applicant would undertake the proposed activities, as requested and conditioned in the application; however, the applicant would be required to undertake additional conditions of approval and monitoring measures as identified by BOEM, in coordination with NMFS and in accordance with the NMFS 2020 BO consultation requirements (i.e., Appendix A: Seismic Survey Mitigation and Protected Species Observer Protocols, B: Gulf of Mexico Marine Trash and Debris Awareness and Elimination Survey Protocols, and C: Gulf of Mexico Vessel Strike Avoidance and Injured/Dead Aquatic Protected Species Reporting Protocols). For the reasons set forth below, inclusion of these measures under Alternative 3 limits or minimizes potential impacts to marine mammals.

Potential Impacts to Marine Mammals from Active Acoustic Sound Sources

Marine mammals exposed to natural or manmade noise may experience physical and psychological effects, ranging in magnitude from none to severe (Southall et al., 2007 and 2019). Four areas of primary concern for marine mammals exposed to elevated noise levels include the following: (1) permanent hearing loss; (2) temporary hearing loss; (3) behavioral response; and (4) masking (Nowacek et al., 2007). Other literature also suggests that there may be non-auditory effects, such as gas-bubble formation and stress.

Scientific uncertainty remains regarding the nature and magnitude of the actual impacts of seismic noise on the behavior of marine mammals, particularly when it comes to distinguishing between a general behavioral response and a biologically significant one. As noted in Southall et al. (2007 and 2019), some of this uncertainty is related to data suffering from low sample sizes, limited information on received sound levels and background noise, insufficient measurements of all potentially important contextual variables, and/or insufficient controls with most behavioral studies suffering from at least some of these problems. In their 2020 BO, NMFS noted that harassment or disturbance is not limited to the 160 dB traditionally used as the standard behavioral disturbance, but should consider a number of other sound characteristics, including the frequency content, duration or repetitive nature of the sound, depth of the source, and movement of the source (USDOC, NMFS, 2020a).

Permanent Hearing Loss

Permanent hearing loss in a marine mammal (i.e., permanent threshold shift [PTS]) is defined as the deterioration of hearing due to prolonged or repeated exposure to sounds that accelerate the normal process of gradual hearing loss (Kryter, 1985) or the permanent hearing damage due to brief exposure to extremely high sound levels (Richardson et al., 1995). PTS results in a permanent elevation in hearing threshold - that is, an unrecoverable reduction in hearing sensitivity (Southall et al., 2007). Direct physical effects, such as PTS, require relatively intense, received energy that would be expected to occur only at short distances from the seismic survey source (Nowacek et al., 2007; Zimmer and Tyack, 2007). According to Southall et al. (2007), PTS for cetaceans from multiple pulse sources (e.g., using seismic airguns) is

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established at 230 dB re 1 μPa (peak). In their 2020 BO, NMFS assumed an 80 percent aversion value to PTS levels of G&G associated sound exposure, which resulted in an estimate of up to 120 individual Bryde’s whales that could be exposed to PTS sound levels (USDOC, NMFS, 2020a) over a 50 year time period without implementation of the proposed closure. The operator does not propose operations or support vessel traffic in the Bryde’s whale area; therefore, these exposures would be reduced or avoided and as a result impacts to the Bryde’s whale are expected to be negligible to minor. In their 2020 BO, NMFS determined that adverse impacts of PTS to sperm whales would be discountable (USDOC, NMFS, 2020a).

Temporary Hearing Loss

Manmade sound may also cause temporary and reversible hearing loss called a temporary threshold shift (TTS), which may continue for minutes to hours or even days. The duration of TTS depends on a variety of factors, including intensity and duration of the auditory stimulus; and recovery can take minutes, hours, or days as well. Animals suffering from TTS over longer time periods, such as hours or days, may be considered to have a change in a biologically significant behavior, as they could be prevented from detecting sounds that are biologically relevant, including communication sounds, sounds of prey, or sounds of predators (U.S. Navy, 2008a and 2008b).

Behavioral Response

In Southall et al. (2007), an expert panel reviewing available literature on behavioral response to anthropogenic noise were unable to reach a consensus on what level of sound may serve as a threshold for behavioral reactions in marine mammals. A number of studies document behavioral effects in response to seismic surveys, primarily for mysticetes (Richardson et al., 1995). Mysticetes are considered low-frequency cetaceans with an estimated auditory bandwidth of 7 Hz to 30 kHz. The Bryde’s whale is included in this low frequency group, though there have been no studies of the response of the Bryde’s whale to seismic sounds (USDOC, NMFS, 2020a). The mysticetes (i.e., baleen whales) have been one of the most studied groups of marine mammals in terms of observations of behavioral changes in response to seismic operations. There is clearly a possible overlap between the expected frequencies of best-hearing sensitivity (low threshold) in mysticetes and maximal airgun output at the source. It is generally considered that the auditory abilities of all mysticete species are broadly similar, based upon vocalization frequencies and ear anatomy (Ketten, 1998). Given that no direct audiograms of mysticetes have been obtained, it is impossible to define what level of sound above hearing threshold may cause behavioral effects, which would be expected to be variable, complicated, and dependent upon more than simply the received sound level. The mysticete species found in the GOM (i.e., blue, fin, sei, humpback, and minke, whales) are considered rare, extralimital, or uncommon (Würsig et al., 2000), with the exception of the Bryde’s whale, and their occurrence within the proposed action area being potentially affected by noise is not expected.

Sperm whales are a highly vocal species under natural conditions; they produce echolocation clicks almost continuously during dives. They are considered a mid-frequency cetacean with functional hearing of approximately 150 Hz to 160 kHz. Interruption or cessation of their vocal activity has often been cited as a reaction to manmade noise. Watkins and Schevill (1975) showed that sperm whales interrupted click production in response to pinger (6 to 13 kHz) sounds. Mate et al. (1994) reported temporarily decreased sperm whale abundance in an area of seismic operations in the northeastern GOM. However, acoustic arrays recorded sperm whales producing click sequences during dives within 4 nautical miles of an active, 3D seismic vessel during surveys conducted in 2001. NMFS expects that sperm whales exposed to seismic airgun sounds may cease calling or change their vocal behavior. Codas, or sperm whale communication clicks, are not expected to be affected by seismic survey sound at far distances. As stated in their 2020 BO, NMFS expects that sperm whales would not come within 18.2 m of an active airgun array, as they would likely hear and see the array and would not come in close proximity. It is also expected that sperm whales in the GOM may have become habituated or become tolerant to airgun sounds, and may not exhibit a behavioral response (USDOC, NMFS, 2020a). Further, Weir (2008) found few obvious, visible responses of sperm (and humpback) whales to seismic airgun sounds off Angola, although only overt responses were examined, and subtle or longer range responses may not have been detected. If the whales did come within 500 m (the exclusion zone) of the airgun array, the operator is required to shutdown the airgun, as required under Appendix A in the NMFS 2020 BO and as proposed under Alternative 3. However, whales that go unsighted, are below the surface, or beyond the exclusion zone can still be exposed to airgun sound (USDOC, NMFS, 2020a).

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From 2002 to 2005, BOEM funded a multiyear, interdisciplinary study on sperm whales in the GOM, called the Sperm Whale Seismic Study. A summary report was produced in 2006 (Jochens et al., 2006) and a synthesis report was released in 2008 (Jochens et al., 2008). These reports provide the following conclusions regarding sperm whales in the GOM and their response to seismic surveys:

During controlled exposure experiments (CEE), researchers could detect “no horizontal avoidance of the seismic source for exposure levels (RL) of <150 dB re 1 μPa (rms).” Similarly, opportunistic studies detected no apparent horizontal avoidance or displacement of sperm whales associated with operational seismic surveys;

Although a small sample, the CEE data results did not confirm the assumption that whales swim away from an airgun as it ramps up or approaches the whale at full power;

In contrast to the lack of avoidance response, the CEE results showed there may be statistically significant changes in the swimming and foraging behavior of sperm whales exposed to the sound of airguns in the exposure range (RL) of 111-147 dB re 1 μPa (rms) (131-164 dB re 1 μPa [peak to peak]; see Table I in Madsen et al., 2006) at distances of approximately 1.4-12.6 km from the sound source; and

There was the “discovery of a statistically significant 60 percent reduction in foraging for one whale coupled with evidence that other whales are less sensitive…”

Sperm whales are most likely to be acoustically aware of their environment and can exhibit behavioral reactions in a number of ways, including interruption of vocal activity and foraging. However, there are, as yet, insufficient data to assign thresholds for acoustic disturbance to sperm whales. An additional factor to consider is the deep-diving habit of sperm whales. Unlike mysticetes, which may remain close to the surface for long periods, sperm whales spend a small percentage of time at the surface during the course of feeding activity. They surface for longer periods (average 9 minutes) between deeper dives to replenish myoglobin oxygen reserves (Watwood et al., 2006). This means they may be less likely to receive any mitigative effects afforded by sea state and near surface conditions that could buffer or dissipate sound that can occur in some instances. In addition, the sperm whale may dive to a depth where an operating seismic vessel could potentially pass directly over it without visually detecting the sperm whale.

Little is known about the hearing sensitivity of dwarf/pygmy sperm whales. Pulsed sounds with peak frequencies below 13 kHz have been recorded from pygmy sperm whales (Caldwell and Caldwell, 1987), and the anatomical and physiological features of the dwarf sperm whale head have been shown to be consistent with production of echolocation clicks (Cranford et al., 1996; Goold and Clarke, 2000). Audiograms have only recently been obtained for pygmy sperm whales and dwarf sperm whales (Cook et al., 2006; Finneran, 2009; Ridgway and Carder, 2001), but data remain insufficient to ascribe avoidance thresholds. It is possible, however, that these species may, as in the case of sperm whales, be sensitive to a wide range of sound frequencies, including those produced by seismic airgun arrays. This factor, along with their similar deep-diving habits and relatively widespread distributions in the GOM, may warrant concerns for these species from seismic survey activities, similar to those described for the sperm whale.

The Delphinids are also considered mid-frequency cetaceans with functional hearing of approximately 150 Hz to 160 kHz. They represent a diverse group including the true dolphins, killer whales, and pilot whales. There have been few studies of the impact of seismic surveys on species of Delphinidae (e.g., Goold and Fish 1998; Stone and Tasker, 2006; Weir, 2008; Weilgart, 2013). This higher frequency energy must be taken into account when considering seismic interactions with delphinids. Further, and contrary to early perceptions, the high-frequency components of airgun emissions are of sufficient level to exceed the dolphin auditory threshold curve at these low frequencies, even after considerable spreading loss (Goold and Fish, 1998).

Since the delphinid auditory system has a relatively poor response at the low-frequency end (about 110 dB re 1 µPa at 200 Hz; but see Table 2 in Southall et al., 2007) and increases in sensitivity toward the ultrasonic range; there is a clear gradient of increasing sensitivity that exists over a broad frequency range up to the frequency of peak sensitivity. Further, although an airgun pulse will have maximal energy at a few tens of Hertz, with energy decreasing towards the higher frequencies, there is also an increase in dolphin hearing sensitivity in this region. So, although toothed whales specialize in hearing ranges generally outside of the

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majority of seismic survey impulse sounds, there is still the potential for sounds from these surveys to fall within the acoustic sensitivity of toothed whales.

Masking

Auditory masking occurs when a sound signal that is of importance to a marine mammal (e.g., communication calls, echolocation, and environmental sound cues) is rendered undetectable due to the high noise-to-signal ratio in a frequency band relevant to a marine mammal’s hearing range. In other words, noise can cause the masking of sounds that marine mammals need to hear in order to function effectively (Erbe et al., 1999). The presence of the masking noise can make it so that the animal cannot discern sounds of a given frequency. Yet at a given level it would be able to do so in the absence of the masking noise. If sounds used by the marine mammals are masked to the point where they cannot provide the animal with needed information, critical natural behaviors could be disrupted and harm could result (Erbe and Farmer, 1998). In the presence of the masking sounds, the sounds the animal needs to hear must, therefore, be of greater intensity for it to be able to detect and to discern the information in the sound.

In the case of seismic surveys in the GOM, where potential masking noise takes a pulsed form with a low duty cycle (~6-10 %, or a 1-s disturbance in the sound field in every 10-15 s of ambient noise), the effect of masking is likely to be low relative to continuous sounds such as ship noise. Some whales are known to continue calling in the presence of seismic pulses. Their calls can be heard between the seismic pulses (e.g., Richardson et al., 1986; McDonald et al., 1995; Nieukirk et al., 2004; Smultea et al., 2004). Although there is one report that sperm whales ceased calling when exposed to pulses from a very distant seismic ship (Bowles et al,. 1994), more recent studies report that sperm whales continued calling in the presence of seismic pulses (Madsen et al., 2002; Tyack et al., 2003; Smultea et al., 2004; Holst et al., 2006; Jochens et al., 2008). Masking of sonar clicks of foraging females could occur, which could decrease the distance over which males can detect females. However, because of their widespread distribution in the GOM, NMFS does not expect the mating success of sperm whales to be adversely affected in the long-term should masking occur (USDOC, NMFS, 2020a). The lower frequency range of sounds from G&G activities may interfere with the communication among Bryde’s whale, particularly calls from the species to mate (USDOC, NMFS, 2020a).

Non-Auditory Effects

The best available scientific information shows that resonance can occur in marine animals but may not necessarily cause injury, and any such injury is not expected to occur below a sound pressure level of 180 dB re 1 µPa. Damage to the lungs and large sinus cavities of cetaceans from air space resonance is not regarded as a likely significant, non-auditory injury because resonance frequencies of marine mammal lungs are generally below that of the Surveillance Towed Active Sonar System-Low Frequency Active (SURTASS LFA) sonar signal (Finneran, 2003); therefore, they are below the seismic survey source signal. Further, biological tissues are heavily damped, and tissue displacement at resonance is predicted to be exceeding small. Lung tissue damage is generally uncommon in acoustic-related strandings (Southall et al., 2007). Additionally, since there is abundant anatomical evidence that marine mammals have evolved and adapted to dramatic fluctuations in pressure during long, deep dives that seem to exceed their aerobic capacities (Williams et al., 2000), it is very unlikely that significant lung resonance effects could be realized from the proposed seismic survey operations.

Decompression sickness (DCS) may occur as a result of diving to deep depths and then surfacing too quickly, forcing nitrogen bubbles to form in the bloodstream and tissues (Jepson et al., 2003). Historically, there has been much debate on whether marine mammals can suffer from a form of DCS caused by in vivo (in the natural body) nitrogen gas-bubble expansion. However, recent pathological findings of two Risso’s dolphins (Grampus griseus) suggest that, while rare, it is possible as a result of rapid ascent to the surface while struggling with prey during hunting (Fernández et al., 2017). Although more investigation is needed, this study brings to question how exposure to stressful situations, whether from natural (e.g. large prey) or anthropogenic (e.g. military sonar) sources, may affect the diving behavior of marine mammals in order to drive it over a non-reversible condition leading to death. More information is needed to further understand this subject and will require sustained investigation and monitoring. Potential changes in diving behavior as a result of the proposed action are expected to be short-term and temporary. Thus, the proposed action is not likely to cause DCS.

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Studies pertaining to the effects of stress and stress responses in mammals, including studies on marine mammals, have been reviewed by Wright et al. (2007) and Curry (1999). The stress studies investigate physiological responses to disturbance (e.g., increase in stress hormones or heart rate) rather than looking for changes in behavior (e.g., avoidance and disruption of foraging). However, in most cases, the biological importance of stress responses in marine mammals (e.g., effects on energetics, survival, reproduction, and population status) remains unknown.

The prey of Bryde’s whales and sperm whales and the invertebrates that they feed on may exhibit a behavioral response, such as a startle or avoidance response, when exposed to airgun noise. NMFS anticipates a reduction in the availability of prey for sperm whales and the Bryde’s whales in proximity to an active airgun array; however, NMFS does not expect “a meaningful immediate impact on sperm whales [or] Bryde’s whales (USDOC, NMFS, 2020a)”

By selecting Alternative 3, the operator is required to follow the conditions of approval and monitoring measures in Appendix A: Seismic Survey Mitigation and Protected Species Observer Protocols outlined in the NMFS 2020 BO. With these conditions of approval and monitoring measures in place, the impacts to sperm whales, Bryde’s whales, and other marine mammals is determined to be minor.

Potential Impacts to Marine Mammals from Vessel Noise

The effects of noise produced by moving G&G survey vessels on marine mammals are difficult to assess because of the wide array of reports of their observed behavioral responses, both between and within species. Actual responses of individuals could vary widely and are heavily dependent on context (Richardson et al., 1995; Southall et al., 2007; Ellison et al., 2011). Vessel noise can have acute effects such as short-term behavioral and stress response. The nature of behavioral response cetaceans exhibit to vessels may depend on vessel speed, size, and distance from the animal, as well as the number and frequency of vessel encounters (USDOC, NMFS, 2020a). The dominant source of vessel sound from the proposed action is propeller cavitation, although other ancillary sounds may be produced (Richardson et al., 1995). The intensity of sound from vessels is related to size and speed. Large ships tend to be noisier than small ones and ships underway with a full load or towing/pushing produce more sound than unladen vessels (USDOC, NMFS, 2020a). Noise from service-vessel traffic may elicit a startle and/or avoidance reaction from whales and dolphins or mask their sound reception (Tyack, 2008). Vessel noise from the proposed action will produce low levels of noise, generally in the 150 to 170 dB re 1 µPa-m at frequencies below 1,000 Hz. Vessel noise is transitory and generally does not propagate at great distances from the vessel. The NMFS 2020 BO concluded that the effects of vessel noise to sperm whales are not likely to adversely affect the species and Bryde’s whales are likely to be adversely affected from vessel noise (USDOC, NMFS, 2020a). However, the proposed activities are located outside of the area where the Bryde’s whale is likely to be present. The operator does not propose operations or support vessel traffic in the Bryde’s whale area. The behavioral disruptions potentially caused by noise and the presence of vessel traffic will have negligible effects on cetacean populations in the northern GOM.

Potential Impacts to Marine Mammals from Vessel Traffic

Slow-moving cetaceans or those that spend extended periods of time at the surface, and deep-diving species (e.g., sperm whales) while on the surface, might be expected to be the most vulnerable to accidental vessel strike (Vanderlaan and Taggert, 2007). Smaller delphinids often approach vessels that are in transit to bow-ride; however, vessel strikes are less common for these faster moving mammals or are underreported (Wells and Scott, 1997). Florida manatees are commonly found in shallow coastal waters of Florida, but they have been found along the entire northern GOM from Florida to Texas (Fertl et al., 2005), though some recent deepwater sightings have occurred. Vessel strikes are the most common cause of human-induced mortality for manatees (State of Florida, Fish and Wildlife Conservation Commission, 2020), and most manatees bear prop scars from contact with vessels. The vast majority of strikes to manatees result from recreational and fishing vessels, not those related to oil and gas activities.

Worldwide, most vessel strikes of large whales occur when vessels are traveling at speeds greater than approximately 10 knots (Conn and Silber, 2013; Jensen and Silber, 2004; Laist et al., 2001; Vanderlaan and Taggart, 2007). If a vessel strike occurs, the animal may experience no injuries, minor non-serious injuries, serious injuries, or death, which largely depends on the size and speed of the vessel (USDOC, NMFS, 2020a). Both GOM Bryde’s whales and sperm whales are vulnerable to vessel strikes. One confirmed vessel strike to a GOM Bryde’s whale occurred in 2009. While there are no known recent vessel strikes to

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sperm whales, one possible lethal strike occurred in 1990 and a non-lethal strike in 2005. Additionally, a sperm whale is believed to have been struck by a U.S. Navy vessel in 2001 (USDOC, NMFS, 2020a).

The lack of response by sperm whales to oncoming vessels suggest the whales may not hear or see ships approaching or the whales are habituated to the high level of vessel operation activity in the GOM. The Bryde’s whale spends much of its’ time within 15 m of the water surface and at night on the surface, which makes it more likely to be struck by a vessel. With the Bryde’s whale vessel strike mitigation measures required by the NMFS 2020 BO in place and as proposed under Alternative 3, NMFS estimated an annual rate of zero lethal Bryde’s whale vessel strikes per year from oil and gas vessels traffic greater than 10 knots (USDOC, NMFS, 2020a).The proposed activities are located outside of the area where the Bryde’s whale is likely to be present. The operator has not proposed any service vessels or vessel traffic within the Bryde’s whale area. Under Alternative 3, the operator is required to notify BOEM 15 days prior to any vessel transit within the Bryde’s whale area; approval from BOEM is required prior to any vessel transit changes.

In their 2020 BO, NMFS estimated an annual rate of 0.10 vessel strikes likely to result in no or minor injuries to sperm whales per year from oil and gas activities (USDOC, NMFS, 2020a).

By selecting Alternative 3, the operator is required to follow the conditions of approval and monitoring measures in Appendix C: Gulf of Mexico Vessel Strike Avoidance and Injured/Dead Aquatic Protected Species Reporting Protocols outlined above and in the NMFS 2020 BO. With these conditions of approval and monitoring measures in place, the impacts to sperm whales, Bryde’s whales, and other marine mammals is determined to be minor.

Potential Impacts to Marine Mammals from Marine Trash and Debris

Marine debris is a serious concern in the ocean environment. Plastics, in particular, and from many different sources, pose a threat to the environment and a serious threat to marine mammals. Ingestion of plastic has the potential to cause a digestive blockage which may ultimately lead to the death of a marine mammal (Gall and Thompson, 2015). Entanglement also has the potential to result in injury or mortality for marine mammals (Gall and Thompson, 2015). By selecting Alternative 3, the operator is required to follow the Conditions of Approval and monitoring measures in Appendix B: Gulf of Mexico Marine Trash and Debris Awareness and Elimination Survey Protocols outlined above and in the NMFS 2020 BO. With these Conditions of Approval and monitoring measures in place, the impacts to sperm whales, Bryde’s whales, and other marine mammals is determined to be negligible.

Conclusion

The sections above discuss marine mammal hearing in general and the potential range of effects to marine mammals from seismic noise, including: (1) permanent hearing loss; (2) temporary hearing loss; (3) behavioral response; (4) masking; and (5) non-auditory effects. As described, seismic noise has the potential, individually or cumulatively, to result in any of these potential impacts to marine mammal species commonly found in the GOM and proposed action area. However, BOEM finds that the potential for such effects from the proposed action is unlikely to rise to significant levels for the following reasons:

Mysticetes, as low-frequency hearing specialists, are the species groups most likely to be susceptible to impacts from nonpulse sound (intermittent or continuous) given that their hearing ranges overlap most closely with the noise frequencies produced from drilling (Southall et al., 2007 and 2019). However, most mysticete species that may occur in the GOM (i.e., North Atlantic right, blue, fin, sei, humpback, and minke) are considered either “extralimital,” “rare,” or “uncommon” within the GOM (Wursig et al., 2000; Hayes et al., 2019). The only commonly occurring baleen whale in the northern GOM is the Bryde’s whale which is limited in its range. Bryde’s whales are expected to mostly exhibit avoidance behavior and may alter their vocalizations when exposed to seismic surveys (USDOC, NMFS, 2020a). Given the small geographic scope of the proposed action, as well as the operator proposing no survey activity or service vessels through the Bryde’s whale area, the presence of these species within the action area is unlikely. However, the potential for significant impacts is minimized given the implementation of Appendix A: Seismic Survey Mitigation and Protected Species Observer Protocols outlined in NMFS 2020 BO and under Alternative 3.

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Manatees are not typically common in the proposed action area, though some deepwater sightings have occurred. As they predominantly inhabit only coastal marine, brackish, and freshwater areas they are not expected to occur regularly in the area of the proposed action.

The remaining marine mammal species in the GOM are considered either mid-frequency hearing specialists (e.g., sperm whales, beaked whales, and dolphins) with hearing ranges that slightly overlap with sound frequencies produced from seismic noise (Southall et al., 2007), or high-frequency specialists (pygmy and dwarf sperm whales). Therefore, the potential for seismic noise produced from this proposed action to cause auditory and non-auditory effects, PTS, TTS, behavioral changes, or masking on these species is further limited although not entirely eliminated.

To further minimize or reduce the potential for impacts, BOEM requires several mitigation and monitoring requirements under Alternative 3 and the NMFS 2020 BO (Appendix A: Seismic Survey Mitigation and Protected Species Observer Protocols) described below. These measures were developed in coordination with NMFS. They are meant to be conservative (i.e., they afford additional protection to the species). These measures, although needing further testing for effectiveness, represent the best available mitigation strategy for seismic surveys. The measures are expected to minimize duration of exposure to sounds above threshold, when implemented in NMFS Incidental Take Authorizations (ITA) under the MMPA (the regulations have not yet been finalized by NMFS). All PSOs must have completed PSO training in accordance with NMFS National Standards for a Protected Species Observer and Data Management Program: A Model for Seismic Surveys (Baker et al., 2013). The following is a summary of the mitigation and monitoring requirements under Appendix A in the NMFS 2020 BO, applicable for all water depths:

o Establishment of two exclusion zones. For beaked whales, kogia spp., sperm whales, and baleen whales, the exclusion zone encompasses the area at and below the sea surface out to a radius of 1.5 km from the edges of the airgun array. The exclusion zone for all other protected species encompasses the area at and below the sea surface out to a radius of 500-m from the edges of the airgun array (this exclusion zone is then continually monitored for the presence of whales [and sea turtles] by dedicated PSOs).

o Acoustic monitoring by acoustic PSOs to support visual monitoring.

o Shut down of the seismic sound source should a PSO observe a whale within or approaching the exclusion zone.

o Upon implementation of shutdown, the source may be reactivated after the marine mammal(s) have been observed exciting the exclusion zone or following a 30 minute clearance with no further marine mammal(s) observations.

o Slow ramp-up of seismic sound sources at the start or restart of surveys (e.g., the gradual increase in seismic noise) so as to allow an animal to leave the area before the seismic sound reaches potentially disturbing levels.

While the proposed activities will not occur within the Bryde’s whale area, it is possible that the species may travel outside of the habitat closure area, and may still experience impacts from G&G surveys (USDOC, NMFS 2020a).

In conclusion, given the scope, timing, and transitory nature of the proposed action and given the conditions of approval and monitoring requirements in place, the noise related to the proposed seismic survey is not expected to result in PTS, TTS, behavioral change, masking, or non-auditory effects to marine mammals in the GOM that would rise to the level of significance. The geographic scope of the proposed action is small in relation to the ranges of marine mammals in the GOM. The proposed survey activities are not expected to cause long-term or permanent displacement of the animals from preferred habitats, nor will they result in the destruction or adverse modification of any habitats. Survey activities will involve limited vessel traffic related to the towing of the airgun array that carries some risk of collisions; however, animals may avoid the sound source of the moving vessels, reducing the likelihood of collision. BOEM has adopted applicable guidance from the NMFS 2020 BO to minimize/negate the chance of vessel strike to marine mammals: Appendix C: Gulf of Mexico Vessel Strike Avoidance and Injured/Dead Aquatic Protected Species Reporting Protocols. Also, BOEM has adopted applicable guidance from the NMFS 2020 BO to

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minimize/negate the chance of marine trash and debris impacts to marine mammals: Appendix B: Gulf of Mexico Marine Trash and Debris Awareness and Elimination Survey Protocols.

3.2.3. Cumulative Impact Analysis

Chapter 4.2 of the GOM G&G PEIS and Chapter 4.9 of the Multisale EIS and 2018 SEIS address the cumulative impacts on marine mammals as a result of oil and gas leasing, exploration, development and production activities, including G&G activities.

Activities considered under the cumulative scenario which include the GOM oil and gas program and other anthropogenic and natural activities, including the proposed action, may affect protected marine mammals or critical habitat. Marine mammals could be impacted by the degradation of water quality resulting from operational discharges; vessel traffic; noise generated by platforms, drilling rigs, helicopters, vessels, and G&G surveys; explosive structure removals; oil spills; oil-spill-response activities; loss of debris from service vessels and OCS structures; commercial fishing; capture and removal; and pathogens. The cumulative impact on marine mammals is expected to result in a number of chronic and sporadic sublethal effects (i.e., behavioral effects and nonfatal exposure to or intake of OCS-related contaminants or discarded debris) that may stress and/or weaken individuals of a local group or population and predispose them to infection from natural or anthropogenic sources.

Few deaths are expected from chance vessel collisions, ingestion of plastic material, commercial fishing, and pathogens. Deaths as a result of structure removals are not expected to occur due to conditions of approval and monitoring measures that the operator must adhere to during operations. Disturbance (noise from vessel traffic and drilling operations, etc.) and/or exposure to sublethal levels of toxins and anthropogenic contaminants may stress animals, weaken their immune systems, and make them more vulnerable to parasites and diseases that normally would not be fatal. The net result of any disturbance will depend upon the size and percentage of the population likely to be affected, the ecological importance of the disturbed area, the environmental and biological parameters that influence an animal’s sensitivity to disturbance and stress, or the accommodation time in response to prolonged disturbance (Geraci and St. Aubin, 1980). Natural phenomena, such as tropical storms and hurricanes, are impossible to predict but do occur in the GOM though impacts remain difficult to quantify.

Conclusion

The effects of the proposed action, when viewed in light of the effects associated with other relevant activities, may impact marine mammals in the GOM. With the implementation of the required conditions of approval and monitoring measures for seismic survey and vessel operations under Alternative 3, as well as the limited scope, timing, and geographic location of the proposed action, effects from the proposed survey activities on marine mammals will be negligible (vessel noise, marine trash and debris) to minor (acoustic noise, vessel traffic). For animals that may be continuing to experience stress/sublethal impacts from natural or anthropagenic stressors, the additional measures should act to further reduce impacts and provide an abundance of precaution.

3.3. SEA TURTLES

3.3.1. Description

The life history, population dynamics, status, distribution, behavior, and habitat use of sea turtles can be found in Chapter 4.3 and Appendix E of the GOM G&G PEIS and Chapter 4.9 of the Multisale EIS and 2018 SEIS, FWS 2018 BO, and in the NMFS 2020 BO, and is incorporated by reference into this SEA. Of the extant species of sea turtles, five are known to inhabit the waters of the GOM (Pritchard, 1997): the leatherback (Dermochelys coriacea), green (Chelonia mydas), hawksbill (Eretmochelys imbricata), Kemp’s ridley (Lepidochelys kempii), and loggerhead (Carettra caretta). The loggerhead turtle is the most abundant turtle in the GOM (Dodd, 1988). The leatherback turtle is the most abundant turtle in the northern GOM continental slope (Mullin and Hoggard, 2000). These five species are all highly migratory, and individual animals will migrate into nearshore waters as well as other areas of the North Atlantic Ocean, GOM, and Caribbean Sea.

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All five species of sea turtles found in the GOM have been federally listed as endangered or threatened since the 1970’s. Critical habitat was designated for the distinct population segment (DPS) of Northwest Atlantic loggerhead turtles on July 10, 2014 in 79 CFR 79 39755 39854 (Federal Register, 2014).

In 2007, FWS and NMFS published 5-year status reviews for federally listed sea turtles in the GOM (USDOC, NMFS and USDOI, FWS, 2007a-e). A 5-year review is an ESA-mandated process that is conducted to ensure that the listing classification of a species as either threatened or endangered is still accurate. Both agencies share jurisdiction for federally listed sea turtles and jointly conducted the reviews. After reviewing the best scientific and commercially available information and data, agencies determined that the current listing classification for the five sea turtle species remain unchanged. Updated 5-year reviews for hawksbill and leatherback turtles were published in 2013 that support the current listing status for these species (USDOC, NMFS and USDOI, FWS, 2013a and b).

Sea Turtle Hearing

The anatomy of sea turtle ears and measurements of auditory brainstem responses of green and loggerhead sea turtles demonstrate that sea turtles are sensitive to sounds, with an effective hearing range within low frequencies (Bartol et al., 1999; Lenhardt et al., 1983; Moein et al., 1994; Ridgway et al., 1969). Although external ears are absent, sea turtles have a tympanum composed of layers of superficial tissue over a depression in the skull that forms the middle ear. The tympanum acts as additional mass loading to the ear, allowing for reduction in the sensitivity of sound frequencies and increasing low-frequency, bone-conduction sensitivity (Bartol et al., 1999; Lenhardt et al., 1985). Lenhardt et al. (1983) and Moein et al. (1993 and 1994) found that bone-conducted hearing appears to be an effective reception mechanism for sea turtles (i.e., loggerhead and Kemp’s ridley) with both the skull and shell acting as receiving surfaces for water-borne sounds at frequencies of 250-1,000 Hz. By measuring AEP responses of juvenile green sea turtles to tone pip stimuli, Piniak et al. (2016) found that these turtles have a narrow range of underwater and aerial low frequency hearing. Aerial sound pressure thresholds were lower than those underwater, though they detected a larger frequency range underwater (Piniak et al., 2016). Also, sound intensity level thresholds were lower underwater (Piniak et al., 2016). There is relatively little data on sea turtle hearing, though the current understanding is that sea turtles are low frequency hearing specialists, typically hearing frequencies from 30 Hz to 2.0 kHz (or 2,000 Hz), with a range of maximum sensitivity between 100 to 800 Hz, and a narrower frequency range in air (Bartol et al., 1999; Piniak et al., 2012; Popper et al., 2014). The NMFS 2020 BO stated that sea turtles may be affected by sound exposures from airguns and boomers (USDOC, NMFS, 2020a). Unlike marine mammals, sea turtles “do not appear to greatly utilize environmental sound, at least at far distances in the open ocean” (USDOC, NMFS, 2007).


The diversity of a sea turtle’s life history leaves it susceptible to many natural and human impacts, including impacts while it is on land, in the benthic environment, and in the pelagic environment. The IPFs associated with the proposed action that could affect sea turtles include (1) active acoustic sound sources from airguns; (2) vessel noise; (3) vessel traffic; and (4) marine trash and debris. Chapter 4.3 of the GOM G&G PEIS contains a discussion of the potential impacts from survey operations on sea turtles (USDOI, BOEM, 2017a). Additional information about routine impacts from oil and gas activity on sea turtles is addressed in Chapter 4.9 of the Multisale EIS and 2018 SEIS and the NMFS 2020 BO. The discussions are summarized below and are incorporated by reference into this SEA.


If Alternative 1, the No Action Alternative, is selected the applicant would not undertake the proposed activities. Therefore, the IPFs to sea turtles would not occur. For example, there would be no vessel noise or seismic airgun noise that would result in behavioral change, masking, or non-auditory effects to sea turtles, no long-term or permanent displacement of the animals from preferred habitats, and no destruction or adverse modification of any habitats. Since there would be no vessel traffic related to the towing of the airgun array, there would be no risk of collisions with sea turtles.


If Alternative 2, the Proposed Action, is selected the applicant would undertake the proposed activities, as requested and conditioned in the application. Examples of potential impacts to sea turtles without

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implementation of the above referenced conditions of approval and monitoring include, but are not limited to: injury from vessel traffic and disruption of feeding and other behaviors from vessel presence. This Alternative would not adequately limit or negate potential impacts to sea turtles.


If Alternative 3, the Proposed Action with Additional Conditions of Approval, is selected the applicant would undertake the proposed activities, as requested and conditioned in the application; however, the applicant would be required to undertake additional conditions of approval and monitoring measures as identified by BOEM, in coordination with NMFS and in compliance with the NMFS 2020 BO consultation requirements (i.e., Appendix A: Seismic Survey Mitigation and Protected Species Observer Protocols, B: Gulf of Mexico Marine Trash and Debris Awareness and Elimination Survey Protocols, and C: Gulf of Mexico Vessel Strike Avoidance and Injured/Dead Aquatic Protected Species Reporting Protocols). For the reasons set forth below, inclusion of these measures under Alternative 3 limits or negates potential impacts to sea turtles (e.g., vessel strikes, behavioral disruption from vessel presence).

Potential Impacts to Sea Turtles from Active Acoustic Sound Sources

Although little is known about the effects of anthropogenic noise on sea turtles, potential impacts of G&G surveys may include auditory effects (PTS and TTS) and/or behavioral disturbance. There is limited evidence of TTS in sea turtles. In the 1994 study of juvenile loggerheads, sponsored by the U.S. Dept. of the Army, Corps of Engineers (Moein et al., 1994), sea turtles were contained in a pen in shallow water as they were exposed to pulses from a single airgun. Both behavioral and physiological responses were observed. The turtles avoided airgun pulses at received levels at 175-180 dB re 1 μPa but habituated by the third presentation of the sounds. In some cases, habituated animals remained close to the airgun as it was operating. In 10-15 percent of the sea turtles exposed to airgun pulses, a temporary shift in auditory responses was measured. Received levels causing the shift are not known.

Additional studies have noted possible reactions to low-frequency noise, such as that associated with the proposed action, including startle responses and rapid swimming (McCauley et al., 2000a) and swimming toward the surface at the onset of the sound (Lenhardt, 1994). Recent investigations reported that green and loggerhead sea turtles increased their swimming activities when exposed to low-frequency noise; these activities become more erratic as the exposure level increases (McCauley et al., 2000a). Weir (2007) did not document obvious behavioral avoidance to airguns but suggested responsive actions by sea turtles to the vessel and towed equipment. Sea turtles may alter their behaviors when a vessel approaches, and thereby suspend feeding, resting, or interacting with conspecifics. Such disruptions are expected to be temporary, however, and should not affect the overall survival and reproduction of individual turtles.

NMFS, in their 2020 BO, determined PTS to sea turtles to be discountable and that only TTS would occur. Most sea turtles can dive to depths of up to 960 ft (290 m); however, the leatherback sea turtle can dive over 3,000 ft (1,000 m) (Smithsonian, 2018). Should a sea turtle be in close proximity to an airgun, it is expected to move away from sounds produced by an airgun array, and would only experience TTS. Temporary hearing impairment may impact an individual’s ability to hear other airgun sounds or approaching vessels, until hearing has returned (USDOC, NMFS, 2020a). It is common practice for seismic operators in the GOM to implement a “turtle pause” when a sea turtle is spotted by a PSO. A turtle pause is a voluntary practice during which the visual PSO requests that the operator pause the airgun array for six shots to let the turtle float past the array while it is inactive. This six-shot pause is not considered to produce a loss of data/production and, as a result, operators would not have to re-survey the area. Given the scope, timing, and transitory nature of the proposed action, the implementation of Appendix A: Seismic Survey Mitigation and Protected Species Observer Protocols, and that the best available information indicates that sea turtles do not appear to use environmental sound heavily to meet daily needs for survival, the effects to sea turtles from seismic noise are expected to be negligible.

Popper et al. (2014), published sound exposure guidelines for fishes and sea turtles. A sea turtle would need to be close to the seismic sound source at 210 dB cum or >207 dB peak to cause mortal injury (Popper et al., 2014). Low frequency sounds can cause moderate TTS in turtles at relatively near or intermediate vicinity to the source. Continuous sounds can cause masking and behavioral effects, though the consequences for survival of sea turtles are unknown (Popper et al., 2014). Observational evidence suggests

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that sea turtles will exhibit behavioral changes with received sound levels above 175 dB re: 1 µPa (rms) (USDOC, NMFS, 2020a).

The prey of sea turtles and the invertebrates that they feed on may exhibit a behavioral response, such as a startle or avoidance response, when exposed to airgun noise. NMFS anticipates a reduction in the availability of prey for sea turtles in proximity to an active airgun array; however, NMFS does not expect “a meaningful immediate impact on . . . sea turtles” (USDOC, NMFS, 2020a).

Potential Impacts to Sea Turtles from Vessel Noise

The dominant source of noise from vessels is propeller operation, and the intensity of this noise is largely related to ship size and speed. Vessel noise from the proposed action would produce low levels of noise, generally in the 150 to 170 dB re 1 µPa-m at frequencies below 1,000 Hz. Vessel noise is transitory and generally does not propagate at great distances from the vessel. Also, available information indicates that sea turtles do not greatly utilize environmental sound. The NMFS 2020 BO similarly concluded that sound sources associated with vessel movement were not likely to adversely affect sea turtles (USDOC, NMFS, 2020a). The Popper et al. (2014) sound exposure guidelines were broad-ranging and provided non-quantified, generalized guidelines for shipping noise as a low risk of impairment, unless the turtle is in the near field range (within tens of meters), which would pose a moderate risk of TTS that can recover over time. The risk for noise to cause masking and behavior effects range from low to high depending on the location of the turtle relative to the noise (Popper et al., 2014). The effects to sea turtles from vessel noise are expected to be negligible.

Potential Impacts to Sea Turtles from Vessel Traffic

Sea turtles spend at least 3-6 percent of their time at the surface for respiration and perhaps as much as 26 percent of time at the surface for basking, feeding, orientation, and mating (Lutcavage et al., 1997). There is little data available concerning potential sea turtle impacts from accidental vessel strike due to a lack of studies and/or challenges with detecting such impacts (Nelms et al., 2016). Nonetheless, in the GOM, vessel strike from all types of vessels is known to result in sea turtle mortality and injury, with the associated response depending on the size and speed of the vessel (Lutcavage et al. 1997; Work et al., 2010; Nelms et al., 2016). Although sea turtles can move somewhat rapidly, they are still vulnerable to strikes from vessels that are moving at more than four (4) km per hour, which is common in open water (Hazel et al., 2007; Work et al., 2010). Based on the behavioral observations of turtle avoidance of small vessels, green turtles may be susceptible to vessel strikes at speeds as low as two knots (Hazel et al., 2007). Although there have been hundreds of thousands of vessel trips that have been made in support of offshore operations during the past 40 years of OCS oil and gas operations, there have been no reports of OCS-related vessels having struck sea turtles. This is most likely because a strike with a turtle would probably go undetected by larger vessels or strikes are not reported. Despite the lack of on-water reporting, stranding records show that interactions between vessels and sea turtles in the GOM are quite common (USDOC, NMFS, 2020a). Data show that collisions with all types of commercial and recreational vessel traffic are a cause of sea turtle mortality in the GOM (Lutcavage et al., 1997). Both live and dead sea turtles are often found with deep cuts and fractures indicative of collision with a boat hull or propeller (Hazel et al., 2007).

Based on sea turtle density estimates in the GOM, the encounter rates between sea turtles and vessels would be expected to be greater in water depths less than 200 m (656 ft) (USDOC, NMFS, 2007). To further minimize the potential for vessel strikes, BOEM requires operators to implement Appendix C: Gulf of Mexico Vessel Strike Avoidance and Injured/Dead Aquatic Protected Species Reporting Protocols, which contains vessel strike avoidance measures for sea turtles and other protected species. With implementation of these measures and a PSO on the lookout for sea turtles, the NMFS 2020 BO concluded that the risk of collisions between oil/gas-related vessels (including those for G&G, drilling, production, decommissioning, and transport) and sea turtles is appreciably reduced, but strikes may still occur. The NMFS 2020 BO then grants BOEM an Incidental Take Statement that includes a set number of allowable takes of sea turtles by vessel strikes (USDOC, NMFS, 2020a). As per the required reporting under the NMFS 2020 BO Appendix C: Gulf of Mexico Vessel Strike Avoidance and Injured/Dead Aquatic Protected Species Reporting Protocols, BOEM monitors for any takes that have occurred as a result of vessel strikes and also requires that any operator immediately report the striking of any animal (see requirements under Appendix C). To date, there have been no reported strikes of sea turtles by seismic or other geologic survey vessels. Given

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the scope, timing, and transitory nature of the proposed action and with these established conditions of approval and monitoring measures, effects to sea turtles from vessel collisions is expected to be minor.

Potential Impacts to Sea Turtles from Marine Trash and Debris

A variety of trash and debris, which comes from land-based and ocean sources, is commonly observed in the GOM. Turtles may become entangled in drifting debris and ingest fragments of synthetic materials (Gregory, 2009; Gall and Thompson, 2015; Schuyler, 2016). Once entangled, turtles may drown, incur impairment to forage or avoid predators, sustain wounds and infections from the abrasive or cutting action of attached debris, or exhibit altered behavior that threaten their survival (Gall and Thompson, 2015). By selecting Alternative 3, the operator is required to follow the conditions of approval and monitoring measures in Appendix B: Gulf of Mexico Marine Trash and Debris Awareness and Elimination Survey Protocols outlined above and in the NMFS 2020 BO. With these conditions of approval and monitoring measures in place, the impacts to sea turtles is determined to be negligible.

Conclusion

The sections above discuss sea turtle hearing in general and the potential range of effects to sea turtles from the proposed action, including: (1) active acoustic sound sources; (2) vessel noise; (3) vessel traffic; and (4) marine trash and debris. As described, effects of seismic noise on sea turtles will not rise to the level of significance for the following reasons:

The best available scientific information indicates that sea turtles do not greatly use sound in the environment for survival; therefore, disruptions in environmental sound would have little effect.

To further minimize or reduce the potential for impacts, BOEM instituted several key mitigation and monitoring requirements under Appendix A: Seismic Survey Mitigation and Protected Species Observer Protocols. These measures were developed in coordination with NMFS. They are meant to be conservative (i.e., they afford additional protection to the species). The measures are expected to minimize duration of exposure to sounds above threshold.

The scope, timing, and transitory nature of the proposed action will produce limited amounts of seismic noise in the environment.

As described, effects of vessel noise on sea turtles are considered “discountable” (USDOC, NMFS, 2007 and 2020a). The risk of impacts from marine trash and debris would not rise to the level of significance given that BOEM requires compliance with Appendix B: Gulf of Mexico Marine Trash and Debris Awareness and Elimination Survey Protocols. The risk of collisions between sea turtles and vessels associated with the proposed action exist but would not rise to the level of significance given:

BOEM requires compliance with Appendix C: Gulf of Mexico Vessel Strike Avoidance and Injured/Dead Aquatic Protected Species Reporting Protocols, which provides guidelines on monitoring programs to minimize the risk of vessel strikes to sea turtles and other protected species and the reporting of any observations of injured or dead protected species.

The NMFS 2020 BO recognizes that these measures should appreciably reduce the potential for vessel strikes. The NMFS 2020 BO determined vessels strikes are likely to adversely affect sea turtles related to the proposed actions and granted a limited number of Incidental Take Authorizations to BOEM for sea turtle mortalities by vessel strikes. BOEM continues to assess activity for any strikes to ensure this authority is not exceeded. To date, there have been no reported strikes of sea turtles by G&G survey vessels.

The scope, timing, and transitory nature of the proposed action will result in limited opportunity for sea turtles and vessel strikes.


Chapter 4.3 of the GOM G&G PEIS and Chapter 4.9 of the Multisale EIS and 2018 SEIS address the cumulative impacts on sea turtles as a result of oil and gas leasing, exploration, development and production activities, including G&G activities. The information from these documents is incorporated by reference in this EA.

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Activities considered under the cumulative scenario which include the GOM oil and gas program and other anthropogenic and natural activities, including the proposed action, may affect protected sea turtles or critical habitat. Sea turtles may be impacted by the degradation of water quality resulting from operational discharges, vessel traffic, noise generated by platforms, drilling rigs, helicopters and vessels, G&G surveys, explosive structure removals, oil spills, oil-spill-response activities, loss of debris from service vessels and OCS structures, commercial fishing, capture and removal, and pathogens. The cumulative impact of these ongoing OCS activities on sea turtles is expected to result in a number of chronic and sporadic sublethal effects (i.e., behavioral effects and nonfatal exposure to or intake of OCS-related contaminants or discarded debris) that may stress and/or weaken individuals of a local group or population and that may predispose them to infection from natural or anthropogenic sources. Through a systematic review, policy comparison, and stakeholder analysis, Nelms et al. (2016) found that potential impacts of seismic surveys on sea turtles vary (i.e., hearing damage, entanglement, and critical habitat exclusion) and can be obscure due to the lack of research. Thus, understanding the impacts on individuals and populations can be challenging, and additional research is needed (Nelms et al., 2016).

Few deaths are expected from chance collisions with OCS service vessels, ingestion of plastic material, commercial fishing, and pathogens. Few deaths as a result of OCS structure removals may occur but would be minimal due to requisite conditions of approval and monitoring measures. Disturbance (noise from vessel traffic and drilling operations, etc.) and/or exposure to sublethal levels of toxins and anthropogenic contaminants may stress animals, weaken their immune systems, and make them more vulnerable to parasites and diseases that normally would not be fatal. The net result of any disturbance depends upon the size and percentage of the population likely to be affected, the ecological importance of the disturbed area, the environmental and biological parameters that influence an animal’s sensitivity to disturbance and stress, or the accommodation time in response to prolonged disturbance (Geraci and St. Aubin, 1980). A condition of approval is in place to reduce vessel strike mortalities (i.e., Appendix C: Gulf of Mexico Vessel Strike Avoidance and Injured/Dead Aquatic Protected Species Reporting Protocols).

Natural disturbances such as hurricanes can cause significant destruction of nests and topography of nesting beaches (Pritchard, 1980; Ross and Barwani, 1982; Witherington, 1986). Tropical storms and hurricanes are a normal occurrence in the GOM and along the Gulf Coast. Generally, the impacts have been localized and infrequent; however, few areas of the Gulf Coast did not suffer some damage in 2004, 2005, and 2017. Some impacts of the hurricanes, such as loss of beach habitat, continue to impact sea turtles that would have otherwise used those areas as nesting beaches. Increases or decreases in beach armoring and other structures may impact all nesting sea turtles in the areas affected. Hurricanes and tropical activity may temporarily remove some of these barriers to suitable nesting habitat.

Incremental injury effects from the proposed action on sea turtles are expected to be negligible for seismic and vessel noise and minor for vessel collisions and not rise to the level of significance. This is mainly because of the limited scope, duration, and geographic area of the proposed action and the requirements under the NMFS 2020 BO, such as Appendix A: Seismic Survey Mitigation and Protected Species Observer Protocols, B: Gulf of Mexico Marine Trash and Debris Awareness and Elimination Survey Protocols, and C: Gulf of Mexico Vessel Strike Avoidance and Injured/Dead Aquatic Protected Species Reporting Protocols.

Conclusion

The effects of the proposed action, when viewed in light of the effects associated with other relevant activities, may affect sea turtles occurring in the GOM. With the implementation of the required conditions of approval and monitoring measures for seismic survey and vessel operations (Appendix A: Seismic Survey Mitigation and Protected Species Observer Protocols, B: Gulf of Mexico Marine Trash and Debris Awareness and Elimination Survey Protocols, and C: Gulf of Mexico Vessel Strike Avoidance and Injured/Dead Aquatic Protected Species Reporting Protocols) and the scope of the proposed action, incremental effects from the proposed seismic activities on sea turtles will be negligible (acoustic and vessel noise) to minor (vessel strikes). The best available scientific information indicates that sea turtles do not greatly use sound in the environment for survival; therefore, disruptions in environmental sound would have little effect.

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3.4. FISH RESOURCES AND ESSENTIAL FISH HABITAT

3.4.1. Description

The life history, population dynamics, status, distribution, behavior, and habitat use of fish and essential fish habitat can be found in Chapter 4.4 and Appendix E of the GOM G&G PEIS and Chapter 4.7 of the Multisale EIS and 2018 SEIS, and is incorporated by reference into this SEA.

Threatened or Endangered Species

Four GOM fish species, the Gulf sturgeon, smalltooth sawfish, giant manta ray, and Nassau grouper are protected under the ESA. One species of elasmobranch, the oceanic whitetip shark is also protected under the ESA. The Gulf sturgeon (Acipenser oxyrinchus oxyrinchus) was listed as threatened October 30, 1991 (56 CFR §49653, September 30, 1991). Gulf sturgeon is predominantly distributed in the nearshore waters of the northeastern GOM, and currently, the smalltooth sawfish is predominantly distributed in the nearshore waters of south Florida (USDOI, FWS and Gulf States Marine Fisheries Commission, 1995; USDOC, NMFS, 2009). In their 2020 BO, NMFS determined that smalltooth sawfish and their designated critical habitat are not likely to be adversely affected by BOEM’s oil and gas program (USDOC, NMFS, 2020a). The oceanic whitetip shark (Carcharhinus longimanus) was listed as threatened January 30, 2018 under the ESA (83 FR 4153). The EFH for the oceanic whitetip shark in the project area includes localized areas in the central GOM and Florida Keys. The giant manta ray (Manta birostris) was listed as threatened January 22, 2018 under the ESA (83 FR 2916). Although no EFH or critical habitat has been designated, the giant manta rays are widespread in the GOM. Giant manta rays occupy tropical, subtropical, and temperate oceanic waters and productive coastlines and are commonly found offshore in oceanic waters, but are sometimes found feeding in shallow waters (less than 10 m [33]) during the day (Miller and Klimovich, 2016).

Non-ESA-Listed Species

Approximately 1,540 species of fishes are recorded in the GOM and Florida Keys (McEachran, 2009). NOAA, working with the South Atlantic and Gulf of Mexico Fishery Management Councils, manage 71 and 40 fish and crustacean species, respectively, within the Federal waters of the GOM. Distinctive fish assemblages are recognized within broad habitat classes including demersal (soft bottom and hard bottom), coastal pelagic, and oceanic pelagic (epipelagic and midwater) species. Fish are also classified by their movement patterns. Billfishes (marlins and sailfish), swordfish, tuna, and many shark species are considered highly migratory, as they are widely distributed geographically and occur from coastal waters seaward into the open ocean. Highly migratory species move vertically in the water column to feed, usually on a daily basis, and move great geographic distances for feeding or reproduction (USDOC, NMFS, 2006). An example is the Atlantic bluefin tuna, which are known to use the GOM in the spring for spawning grounds (Teo et al., 2007a and 2007b; Teo and Block, 2010).

Essential Fish Habitat

The Magnuson-Stevens Fishery Conservation and Management Act (MCFMA), as amended in 1996 by the Sustainable Fisheries Act, mandates that the regional Fishery Management Councils, through Fishery Management Plans, describe and identify EFH for each federally managed species, minimize adverse effects on such habitat caused by fishing, and identify other actions that encourage the conservation and enhancement of such habitats. Almost the entire GOM is within a designated EFH. Further, the GOM regional Fishery Management Council amended their GOM plans (referred to as Generic Amendment Number 3, 2005) to more specifically designate that habitats less than 100 fathoms (600 ft) are identified and described as EFH.

Fish Hearing

All fish species have hearing and skin-based mechanosensory systems (inner ear and lateral line) used to detect sound in their environment (Fay and Popper, 2000; Popper, 2003). These sounds may be produced by other fish, other organisms (e.g., snapping shrimp, marine mammals), or other naturally occurring sounds such as waves breaking on the shore, rain on the water surface, etc. Many Gulf fish species are known to actively use sound to mediate specific behaviors (e.g., spawning). Anthropogenic (human-generated) sounds may affect fishes through auditory masking, behavioral modification, temporary hearing

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loss, or physiological injury. Masking of important environmental sounds or social signals could potentially reduce foraging success, increase predation, or disrupt reproduction. Studies suggest responses to anthropogenic sound can vary, even among members of a species. However, startle responses generally include avoidance behaviors away from adverse conditions. Responses may also vary with duration and frequency of exposure to a given signal. Fishes in close proximity to intense sound sources may experience temporarily reduced hearing sensitivity or TTS. These effects depend upon the type of sound, duration of sound, distance of sound, and fish species (Popper and Hastings, 2009). Injury to fishes as a result of rapid changes in pressure (barotrauma) may occur in close proximity to an intense sound source.

Hearing mechanisms in fishes have been studied extensively (Fay and Popper, 2000; Ladich and Popper, 2004; Webb et al., 2008), but the specific capabilities of species and the received-sound levels where potentially adverse impacts may occur are not well known. Furthermore, Popper and Fay (2011) suggest the broad designation of fishes as “hearing specialists” and “hearing generalists” is not sufficient to classify the hearing abilities of fishes. They recommend that the range of hearing capabilities across species is more like a continuum that includes the relative contributions of hydrostatic pressure to the overall hearing capabilities of a species. Although studies have investigated physiological impacts (McCauley et al., 2000c; McCauley et al., 2003) and behavioral response (Skalski et al., 1992; Engas et al., 1996; Slotte et al., 2004; Lokkeborg et al., 2012; Fewtrell and McCauley, 2012) in several species, results are generally inconclusive and cannot be applied at the population level (National Science Foundation, 2011). However, information gaps are widely recognized (Hawkins et al., 2014; Popper et al., 2014) and broad guidance has been developed to minimize potential impacts to fishes and sea turtles resulting from anthropogenic sound exposure. The sections below provide a synopsis of the available information relevant to the effects on fish from exposure to seismic and other anthropogenic sound.


Distinctive fish assemblages can be found within a broad range of habitats in continental shelf and oceanic waters. The IPFs associated with the proposed action that could affect fish include (1) active acoustic sound sources from airguns; (2) vessel noise; and (3) vessel traffic. Chapter 4.4 of the GOM G&G PEIS contains a discussion of the potential impacts from survey operations on fish resources (USDOI, BOEM, 2017a). Additional information about routine impacts from oil and gas activity on fish is addressed in Chapter 4.7 of the Multisale EIS and 2018 SEIS and the NMFS 2020 BO. The discussions are summarized below and are incorporated by reference into this SEA.


If Alternative 1, the No Action Alternative, is selected the applicant would not undertake the proposed activities; therefore, the IPFs to fish would not occur. For example, there would be no seismic airgun noise that would result in behavioral change, masking, or non-auditory effects to the animals, no long-term or permanent displacement of the animals from preferred habitats, and no destruction or adverse modification of any habitats.


If Alternative 2, the Proposed Action, is selected the applicant would undertake the proposed activities, as requested and conditioned in the application. As described in the analyses below, impacts to fish from the proposed action (e.g., hearing loss or behavioral disruption from seismic noise), are expected to be short-term, localized and not lead to significant impacts. Although the conditions of approval and monitoring measures outlined in Chapter 2.4 and discussed in the marine mammal and sea turtle sections are requisite for permit approval, their implementation will not increase or decrease the potential for effects to fish from the proposed action.


If Alternative 3, the Proposed Action with Additional Conditions of Approval, is selected, the applicant would undertake the proposed activities, as requested and conditioned in the application; however, the applicant would be required to undertake additional conditions of approval and monitoring measures as identified by BOEM, in coordination with NMFS and in compliance with the NMFS 2020 BO consultation requirements. As described in the analyses below, impacts to fish from the proposed action (e.g., hearing loss or behavioral disruption from seismic noise), are expected to be short-term, localized and not lead to

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significant impacts. Although the conditions of approval and monitoring measures outlined in Chapter 2.4 would be included, their implementation would not increase or decrease the potential for effects to fish from the proposed action.

Potential Impacts to Fish from Active Acoustic Sound Sources

Fish ears respond to changes in pressure and particle motions (van Bergeijk, 1967; Schuijf, 1981; Kalmijn, 1988 and 1989; Schellert and Popper, 1992; Hawkins, 1993; Fay, 2005). Fish exposed to natural or manmade sound may experience physical and behavioral effects, ranging in magnitude from negligible to severe. The four areas of primary concern for fish exposed to elevated noise levels include: (1) hearing loss; (2) behavioral response; (3) masking; and (4) non-auditory effects.

Hearing Loss

To result in hearing loss, a sound must exceed the specific hearing threshold of that fish for a certain period of time (Popper, 2005). The consequences of temporary or permanent hearing loss in individual fish or a fish population is largely unknown. However, it likely depends upon the number of individuals affected and whether critical behaviors involving sound (e.g., predator avoidance, prey capture, orientation and navigation, reproduction, etc.) are adversely affected.

McCauley et al. (2003) found that caged pink snapper exposed to airgun sounds (600 pulses with peak-to-peak source levels of approximately 223 dB re 1 μPa) experienced observable anatomical damage to the auditory structures and that this damage did not repair 58 days after exposure. The damage as quantified by missing hair cells was relatively low, but the potential for impaired function in the remaining cells and the wider implications of potentially reduced fitness were not tested. Popper et al. (2005) documented TTS of northern pike and lake chub in the Mackenzie River Delta but found that broad whitefish receiving a source level of 177 dB re 1 μPa2 s showed no TTS. In both cases, the repetitive exposure to sound was greater than is expected in a typical seismic survey. Fishes involved in the study by Popper et al. (2005) were examined for damage to the sensory cells of the inner ear as a result of exposure to seismic sound, and no damage was observed (Song et al., 2008).

Behavioral Response

Behavioral effects from seismic noise on fishes can include changes in distribution, migration, mating, and ability to be caught. In general, any adverse effects on fish behavior or fisheries due to G&G surveys may depend on the species in question and the nature of the fishery (i.e., season, duration, and fishing method). Responses may also depend on the age of the fish, motivational state, size, and numerous unknown factors that are difficult, if not impossible, to quantify. Studies investigating the effects of sound (including seismic survey sound) on fish behavior were conducted on both uncaged and caged individuals (Chapman and Hawkins, 1969; Pearson et al., 1992; Santulli et al., 1999; Wardle et al., 2001; Hassel et al., 2003; Boeger et al., 2006) noted that fish typically exhibited a sharp “startle” response at the onset of a sound, followed by a return to normal behavior after the sound ceased. Investigation by Jorgenson and Gyselman (2009) indicated that behavioral characteristics of Arctic riverine fishes were generally unchanged by exposure to airgun sound.

Disturbance to fish population structures and distributions could result in reduced catch. An example would be temporary displacement of fish from traditional fishing grounds. Hirsh and Rodhouse (2000) reviewed studies investigating the hypothesis that seismic survey sounds have a deleterious effect on (usually commercial) fishing success. In most cases, these studies (e.g., Skalski et al., 1992; Engås et al., 1996) found that fishing catch of one or more target species declined with the onset of seismic survey operations and remained depressed throughout this activity and for days after. These effects, as reviewed in Boertmann et al. (2010), depend on species, fishing gear, and other environmental parameters. Further, reduced catch rates have been reported in some marine fisheries during seismic surveys; in several cases the findings are confounded by other sources of disturbance (Dalen and Raknes, 1985; Dalen and Knutsen, 1986; Løkkeborg, 1991; Skalski et al., 1992; Engås et al., 1996). No change was determined in catch-per-unit-effort of fish when airgun pulses were emitted, particularly in the immediate vicinity of the seismic survey (Pickett et al., 1994; La Bella et al., 1996; Wardle et al., 2001). For certain species, reductions in catch may have resulted from a change in behavior of the fish, such as a change in vertical or horizontal distribution (Slotte et al., 2004) and simply coincided with the seismic work.

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Masking

Masking is defined as the effect of an acoustic sound source interfering with the reception and detection of an acoustic signal or other sound of biological importance to a receiver. Any sound within an animal’s hearing range can mask relevant sounds. Theoretically, the airguns or airgun arrays and vessel sound could contribute minimally to localized, short-term, and transitory masking of sound detection by some marine fishes, at least those species whose sound detection capacities are in the frequency range of the seismic survey sound source(s). However, there have been no documented studies concluding that seismic surveys resulted in the masking of any biologically relevant sounds for any fish species. This is most likely due to the roving nature of the G&G surveys or the limited exposure area where survey-related energy can be found. For example, some surveying technologies (e.g., vibroseis) may have operational frequencies or cycles that present an increased potential for locally masking biologically relevant sounds. For a discussion of the biological relevance of ambient and signal sounds to fish, see Fay and Popper (2000).

Non-Auditory Effects

Existing research suggests there is a potential for non-auditory injury or mortality of fish in the immediate vicinity of a high-energy acoustic source. Airguns and airgun arrays may potentially injure or kill fishes within several meters at the time of discharge (Kostyvchenko, 1973; Dalen and Knutsen, 1986; Booman et al., 1996; Dalen et al., 1996). The potential for injury is greater among fishes with trapped gas pockets or swim bladders that expand and contract with the ambient pressure changes. There are few studies that specifically investigate the effects of airgun sound on fish larvae and eggs, but existing research suggests these life stages are no more vulnerable to intense sound than adult fishes. Other studies document no egg, larvae, or fish mortality resulting from exposure to seismic sources (Falk and Lawrence, 1973; Holliday et al., 1987; La Bella et al., 1996; Santulli et al., 1999; McCauley et al., 2000b and 2000c; Thomsen, 2002; Hassel et al., 2003; McCauley et al., 2003; Popper, 2005; Payne et al., 2009).

Physiological effects may also include cellular and/or biochemical responses by fish to acoustic stress. Such stress potentially affects fish by increasing mortality or reducing reproductive success. However, primary and secondary stress responses of fish after exposure to seismic survey sound appear temporary (Sverdrup et al., 1994; McCauley et al., 2000b and 2000c). The periods necessary for these biochemical changes to return to normal are variable and depend on numerous aspects of the biology of the species and of the sound stimulus. The effects to fish from acoustic sound sources are expected to be negligible.

Potential Impacts to Fish from Vessel Noise

The proposed action is not within Gulf sturgeon habitat; however, Gulf sturgeon may be exposed to vessel noise when support vessels transit across their habitat. While the Gulf sturgeon may be able to detect passing vessels, they are not expected to be affected by the sound. According to the NMFS 2020 BO, the effects of vessel noise would be insignificant to the Gulf sturgeon (USDOC, NMFS, 2020a). Therefore, the effects to fish from vessel noise are expected to be negligible.

Potential Impacts to Fish from Vessel Traffic

In the last five year NMFS species review, vessel strikes were identified as an emerging threat for Gulf sturgeon. The NMFS 2020 BO Effects Analysis for Gulf sturgeon estimated one nonlethal and 21 lethal vessel strikes would occur over 50 years as a result of vessels associated with the proposed action. The effects to giant manta rays and oceanic white tip sharks from vessel strikes are discountable (USDOC, NMFS 2020a). The operator is required to adhere with the mitigation and monitoring measures provided in the NMFS 2020 BO under Appendix C: Gulf of Mexico Vessel Strike Avoidance and Injured/Dead Aquatic Protected Species Reporting Protocols. Compliance with the regulations as clarified in the NMFS 2020 BO should reduce or avoid impacts from vessel strikes under this alternative. With these conditions of approval and monitoring measures in place, the impacts to the Gulf sturgeon and other fish species is negligible.

Conclusion

Noise from the proposed action could potentially result in acute injury and mortality of a minimal number of individuals of some species of fish, their larvae, and/or eggs when in very close proximity to a high-energy acoustic source. The proposed action may result in short-term, localized behavioral reactions. Highly migratory species like the bluefin tuna are found in the proposed action area at certain times of the

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year. However, given the small area and timeframe exposed to seismic noise under the proposed action, the transience of the moving seismic source relative to the GOM, and the small number of fish potentially within this localized area, the chance of non-auditory injury or mortality would be limited to an insignificant number of individuals. Seismic effects on such a small number of individuals would be insignificant at the population scale and considerably smaller than the natural mortality rate. Therefore, based on the limited best available science, seismic surveys are not expected to result in significant auditory or non-auditory injury or mortality on marine fish at the population scale. Finally, the frequency range of some G&G survey equipment (e.g., airguns) overlaps with the likely hearing range of the ESA-listed fish species; however, neither of these species are found routinely beyond state waters.


Cumulative impacts on fish and EFH that result from oil and gas leasing, exploration, development, and production activity including G&G activities are discussed in Chapter 4.4 of the GOM G&G PEIS, and Chapter 4.7 of the Multisale EIS and 2018 SEIS. The information from these documents is incorporated by reference in this SEA.

Activities considered under the cumulative scenario include the GOM oil and gas program and other anthropogenic and natural activities, including the proposed action, may affect fish and fisheries. Degradation of water quality from multiple human activities as described in the GOM G&G PEIS, Multisale EIS and 2018 SEIS will continually affect fish and fisheries species. The cumulative impact of these ongoing OCS activities on fish and fisheries is expected to result in a number of chronic and sporadic lethal and sublethal (behavioral effects and nonfatal exposure to or intake of OCS-related contaminants or discarded debris) effects that may stress and/or weaken individuals of a local group or population and predispose them to infection from natural or anthropogenic sources. Finally, non-anthropogenic sources such as red tides and tropical storms may add to the cumulative impacts on fish resources in the northern GOM. The proposed action is a short-term event in a portion of the GOM; therefore, the effects from the proposed action will be slight in regards to these ongoing impacts.

The net result of any disturbance depends upon the size and percentage of the population likely to be affected, the ecological importance of the disturbed area, the environmental and biological parameters that influence an animal’s sensitivity to disturbance and stress, and the accommodation time in response to prolonged stress.

Conclusion

The effects of the proposed action, when viewed in light of the effects associated with other relevant activities, may impact fish and fisheries occurring in the GOM. However, given the scope of the proposed action, incremental effects from the proposed seismic activities on fish and fisheries will be negligible.

3.5. OTHER CONSIDERATIONS A discussion of the other resources considered but not analyzed under this SEA is found in Chapter 4 of the GOM G&G PEIS (USDOI, BOEM, 2017a) and Chapter 3 of the Multisale EIS and 2018 SEIS (USDOI, BOEM, 2017b and c).

4. CONSULTATION AND COORDINATION The information in this SEA was developed by BOEM subject matter experts and in consultation with other Federal agencies, the private sector, and academia personnel found in Chapter 6 of the GOM G&G PEIS and Chapter 5 of the Multisale EIS and 2018 SEIS (USDOI, BOEM, 2017a, b, and c).

The ESA establishes a national policy designed to protect and conserve threatened and endangered species and the ecosystems upon which they depend. Section 7(a)(2) of the ESA requires each Federal agency to ensure that any action that they authorize, fund, or carry out is not likely to jeopardize the continued existence of a listed species or result in the adverse modification of designated critical habitat. On April 20, 2018, the FWS issued its 10-year programmatic BO (FWS 2018 BO) for BOEM and BSEE’s oil and gas activities in the GOM. The FWS 2018 BO does not include any terms and conditions for the protection of endangered species that the Bureaus, lessees, or operators must implement. The FWS 2018 BO also noted that any future consultations may be informal, dependent upon the likelihood of take.

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On March 13, 2020, NMFS issued a Programmatic BO (NMFS 2020 BO) and related terms and conditions for oil and gas activities in the GOM for the protection of these species, including holding lease sales. The NMFS 2020 BO addresses any future lease sales and any approvals issued by BOEM and BSEE, under both existing and future OCS oil and gas leases in the GOM, over a 10-year period. Applicable terms and conditions and reasonable and prudent measures from the NMFS 2020 BO will be applied at the lease sale stage; other specific conditions of approval will also be applied to post-lease approvals. The NMFS 2020 BO may be found here:

https://www.fisheries.noaa.gov/resource/document/biological-opinion-federally-regulated-oil-and-gas-program-activities-gulf-mexico.

The Appendices and protocols may be found here:

https://www.fisheries.noaa.gov/resource/document/appendices-biological-opinion-federally-regulated-oil-and-gas-program-gulf-mexico.

BOEM petitioned NMFS for rulemaking under the MMPA, to assist industry in obtaining incidental take coverage for marine mammals due to oil and gas geological and geophysical (G&G) surveys in the GOM. If NMFS issues a final rule as a result of the petition, the NMFS 2020 BO may be amended and additional mitigation measures beyond what is currently within Appendix A and C may be imposed through Letters of Authorizations under the rule.

BOEM completed consultation with NOAA’s NMFS regarding the MFCMA on July 10, 2017, by the receipt of a comment letter from NMFS. The NMFS letter acknowledged their receipt of the Essential Fish Habitat (EFH) Assessment and the supporting 2017-2022 Multisale Lease NEPA document, provided a determination that the Programmatic Consultation was an appropriate mechanism to evaluate EFH impacts and confirmed the adoption of the BOEM/BSEE mitigation measures outlined in the June 8, 2016 BOEM EFH Assessment to ensure adverse impacts are avoided, minimized, and offset. This consultation remains in effect for 2017-2022 activities or earlier but not if modifications are made to the BOEM/BSEE programs that would result in changes to potential adverse effects on EFH which would trigger additional consultation.

In accordance with the National Historic Preservation Act (54 U.S.C. §§ 300101 et seq.), Federal agencies are required to consider the effects of their undertakings on historic properties. The implementing regulations for Section 106 of the National Historic Preservation Act, issued by the Advisory Council on Historic Preservation (36 CFR §800), specify the required review process. In accordance with 36 CFR § 800.8(c), BOEM intends to use the NEPA substitution process and documentation for preparing an EIS/ROD or an EA/FONSI to comply with Section 106 of the National Historic Preservation Act in lieu of 36 CFR §§ 800.3-800.6.

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6. PREPARERS Denise G. Matherne – NEPA Coordinator; Physical Scientist Hayley Karrigan – Marine Mammals and Sea Turtles; Protected Species Issues Beth Nord – Marine Mammals and Sea Turtles; Protected Species Issues Arie Kaller – Fish; Marine Biologist

7. REVIEWERS Annette Ehrhorn – Senior EnvironmentalScientist Perry J. Boudreaux – Chief, Environmental Operations Section

Documents

UNITED STATES DEPARTMENT OF THE INTERIOR BUREAU OF … · The Proposed Action: LLOG Exploration Offshore, L.L.C. (LLOG) proposes to conduct a zero-offset, offset, or walkaway vertical